diff --git a/Cardiopulmonarybypasssystems/App.xaml.cs b/Cardiopulmonarybypasssystems/App.xaml.cs
index 557a18d..73eb7b7 100644
--- a/Cardiopulmonarybypasssystems/App.xaml.cs
+++ b/Cardiopulmonarybypasssystems/App.xaml.cs
@@ -19,14 +19,30 @@ public partial class App : Application
 
         var services = new ServiceCollection();
         services.AddSingleton<IStandardRepository, StandardRepository>();
+        services.AddSingleton<IPasswordAccessService, PasswordAccessService>();
         services.AddSingleton<IModbusTelemetryService, ModbusTelemetryService>();
         services.AddSingleton<IRs485PumpFlowService, Rs485PumpFlowService>();
         services.AddSingleton<IPumpActuationService, Rs485PumpActuationService>();
+        services.AddTransient<StartupPasswordViewModel>();
+        services.AddTransient<StartupPasswordWindow>();
         services.AddSingleton<MainViewModel>();
         services.AddSingleton<MainWindow>();
 
         _serviceProvider = services.BuildServiceProvider();
 
+        var passwordAccessService = _serviceProvider.GetRequiredService<IPasswordAccessService>();
+        var passwordStatus = passwordAccessService.GetStatus();
+        if (passwordStatus.ShouldPromptAtStartup)
+        {
+            var passwordWindow = _serviceProvider.GetRequiredService<StartupPasswordWindow>();
+            var passwordResult = passwordWindow.ShowDialog();
+            if (passwordResult != true || !passwordAccessService.GetStatus().CanLaunch)
+            {
+                Shutdown();
+                return;
+            }
+        }
+
         var mainWindow = _serviceProvider.GetRequiredService<MainWindow>();
         mainWindow.Show();
     }
diff --git a/Cardiopulmonarybypasssystems/Models/PasswordAccessStatus.cs b/Cardiopulmonarybypasssystems/Models/PasswordAccessStatus.cs
new file mode 100644
index 0000000..5ea45c8
--- /dev/null
+++ b/Cardiopulmonarybypasssystems/Models/PasswordAccessStatus.cs
@@ -0,0 +1,16 @@
+namespace Cardiopulmonarybypasssystems.Models;
+
+public sealed class PasswordAccessStatus
+{
+    public int Stage { get; init; }
+    public bool CanLaunch { get; init; }
+    public bool IsPermanent { get; init; }
+    public bool ShouldPromptAtStartup { get; init; }
+    public bool CanSubmitPassword { get; init; }
+    public bool RequiresPassword => !CanLaunch;
+    public string StageText { get; init; } = string.Empty;
+    public string StatusTitle { get; init; } = string.Empty;
+    public string StatusDetail { get; init; } = string.Empty;
+    public int RemainingDays { get; init; }
+    public DateTime? ExpiresAt { get; init; }
+}
diff --git a/Cardiopulmonarybypasssystems/Services/IPasswordAccessService.cs b/Cardiopulmonarybypasssystems/Services/IPasswordAccessService.cs
new file mode 100644
index 0000000..21c1d1f
--- /dev/null
+++ b/Cardiopulmonarybypasssystems/Services/IPasswordAccessService.cs
@@ -0,0 +1,9 @@
+using Cardiopulmonarybypasssystems.Models;
+
+namespace Cardiopulmonarybypasssystems.Services;
+
+public interface IPasswordAccessService
+{
+    PasswordAccessStatus GetStatus();
+    bool TryUnlock(string password, out PasswordAccessStatus status, out string message);
+}
diff --git a/Cardiopulmonarybypasssystems/Services/PasswordAccessService.cs b/Cardiopulmonarybypasssystems/Services/PasswordAccessService.cs
new file mode 100644
index 0000000..228a274
--- /dev/null
+++ b/Cardiopulmonarybypasssystems/Services/PasswordAccessService.cs
@@ -0,0 +1,228 @@
+using System.IO;
+using System.Text.Json;
+using Cardiopulmonarybypasssystems.Models;
+
+namespace Cardiopulmonarybypasssystems.Services;
+
+public sealed class PasswordAccessService : IPasswordAccessService
+{
+    private const int ExpirationReminderDays = 3;
+    private const string SettingsDirectoryName = "Cardiopulmonarybypasssystems";
+    private const string StatusFileName = "password-access.json";
+    public const string FirstStagePassword = "152026";
+    public const string SecondStagePassword = "302026";
+    private const int FirstStageDays = 15;
+    private const int SecondStageDays = 30;
+
+    private static readonly string StatusFilePath = Path.Combine(
+        Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+        SettingsDirectoryName,
+        StatusFileName);
+
+    public PasswordAccessStatus GetStatus()
+    {
+        var state = LoadState();
+        return BuildStatus(state, persistState: true);
+    }
+
+    public bool TryUnlock(string password, out PasswordAccessStatus status, out string message)
+    {
+        var normalizedPassword = password?.Trim() ?? string.Empty;
+        var state = LoadState();
+        var currentStatus = BuildStatus(state, persistState: true);
+
+        if (currentStatus.IsPermanent)
+        {
+            status = currentStatus;
+            message = "当前版本已永久有效，不需要再输入密码。";
+            return true;
+        }
+
+        if (currentStatus.Stage == 1 && currentStatus.CanLaunch)
+        {
+            status = currentStatus;
+            message = "第 1 阶段仍在有效期内，无需再次输入密码。";
+            return true;
+        }
+
+        if (currentStatus.Stage == 2 && currentStatus.CanLaunch)
+        {
+            status = currentStatus;
+            message = "第 2 阶段仍在有效期内，无需再次输入密码。";
+            return true;
+        }
+
+        var nextStage = currentStatus.Stage switch
+        {
+            <= 0 => 1,
+            1 => 2,
+            _ => 0
+        };
+
+        if (nextStage == 0)
+        {
+            status = BuildStatus(state, persistState: true);
+            message = "当前版本已转为永久有效，不再需要密码。";
+            return true;
+        }
+
+        var expectedPassword = nextStage == 1 ? FirstStagePassword : SecondStagePassword;
+        if (!string.Equals(normalizedPassword, expectedPassword, StringComparison.Ordinal))
+        {
+            status = currentStatus;
+            message = $"密码错误，请输入第 {nextStage} 次时效密码。";
+            return false;
+        }
+
+        var now = DateTime.Now;
+        var expiresAt = now.AddDays(nextStage == 1 ? FirstStageDays : SecondStageDays);
+        var nextState = new PasswordAccessState
+        {
+            Stage = nextStage,
+            ActivatedAt = now,
+            ExpiresAt = expiresAt
+        };
+
+        SaveState(nextState);
+        status = BuildStatus(nextState, persistState: false);
+        message = nextStage == 1
+            ? $"第 1 次时效已生效，有效期至 {expiresAt:yyyy-MM-dd HH:mm}。"
+            : $"第 2 次时效已生效，有效期至 {expiresAt:yyyy-MM-dd HH:mm}；到期后自动转为永久有效。";
+        return true;
+    }
+
+    private static PasswordAccessStatus BuildStatus(PasswordAccessState? state, bool persistState)
+    {
+        if (state is null || state.Stage <= 0)
+        {
+            return new PasswordAccessStatus
+            {
+                Stage = 0,
+                CanLaunch = false,
+                IsPermanent = false,
+                ShouldPromptAtStartup = true,
+                CanSubmitPassword = true,
+                StageText = "当前阶段：未开始",
+                StatusTitle = "需要输入第 1 次时效密码",
+                StatusDetail = $"输入 15 天密码后进入系统。",
+                RemainingDays = 0
+            };
+        }
+
+        if (state.Stage >= 3)
+        {
+            return new PasswordAccessStatus
+            {
+                Stage = 3,
+                CanLaunch = true,
+                IsPermanent = true,
+                ShouldPromptAtStartup = false,
+                CanSubmitPassword = false,
+                StageText = "当前阶段：永久有效",
+                StatusTitle = "系统已永久有效",
+                StatusDetail = "当前可直接进入系统。",
+                RemainingDays = int.MaxValue
+            };
+        }
+
+        var now = DateTime.Now;
+        if (state.ExpiresAt > now)
+        {
+            var remainingDays = Math.Max(1, (int)Math.Ceiling((state.ExpiresAt.Value - now).TotalDays));
+            return new PasswordAccessStatus
+            {
+                Stage = state.Stage,
+                CanLaunch = true,
+                IsPermanent = false,
+                ShouldPromptAtStartup = state.Stage == 1 && remainingDays <= ExpirationReminderDays,
+                CanSubmitPassword = state.Stage == 1 && remainingDays <= ExpirationReminderDays,
+                StageText = state.Stage == 1 ? "当前阶段：第 1 次时效（15 天）" : "当前阶段：第 2 次时效（30 天）",
+                StatusTitle = state.Stage == 1 && remainingDays <= ExpirationReminderDays ? "第 1 次时效即将到期" : "时效有效",
+                StatusDetail = state.Stage == 1 && remainingDays <= ExpirationReminderDays
+                    ? $"剩余 {remainingDays} 天，可提前输入 30 天密码。"
+                    : $"当前可直接进入系统。",
+                RemainingDays = remainingDays,
+                ExpiresAt = state.ExpiresAt
+            };
+        }
+
+        if (state.Stage == 1)
+        {
+            return new PasswordAccessStatus
+            {
+                Stage = 1,
+                CanLaunch = false,
+                IsPermanent = false,
+                ShouldPromptAtStartup = true,
+                CanSubmitPassword = true,
+                StageText = "当前阶段：第 1 次时效已到期",
+                StatusTitle = "需要输入第 2 次时效密码",
+                StatusDetail = $"输入 30 天密码后继续使用。",
+                RemainingDays = 0,
+                ExpiresAt = state.ExpiresAt
+            };
+        }
+
+        var permanentState = new PasswordAccessState
+        {
+            Stage = 3,
+            ActivatedAt = state.ActivatedAt,
+            ExpiresAt = null
+        };
+
+        if (persistState)
+        {
+            SaveState(permanentState);
+        }
+
+        return new PasswordAccessStatus
+        {
+            Stage = 3,
+            CanLaunch = true,
+            IsPermanent = true,
+            ShouldPromptAtStartup = false,
+            CanSubmitPassword = false,
+            StageText = "当前阶段：永久有效",
+            StatusTitle = "系统已永久有效",
+            StatusDetail = "当前可直接进入系统。",
+            RemainingDays = int.MaxValue
+        };
+    }
+
+    private static PasswordAccessState? LoadState()
+    {
+        try
+        {
+            if (!File.Exists(StatusFilePath))
+            {
+                return null;
+            }
+
+            var json = File.ReadAllText(StatusFilePath);
+            return JsonSerializer.Deserialize<PasswordAccessState>(json);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private static void SaveState(PasswordAccessState state)
+    {
+        var directory = Path.GetDirectoryName(StatusFilePath);
+        if (!string.IsNullOrWhiteSpace(directory))
+        {
+            Directory.CreateDirectory(directory);
+        }
+
+        var json = JsonSerializer.Serialize(state, new JsonSerializerOptions { WriteIndented = true });
+        File.WriteAllText(StatusFilePath, json);
+    }
+
+    private sealed class PasswordAccessState
+    {
+        public int Stage { get; set; }
+        public DateTime ActivatedAt { get; set; }
+        public DateTime? ExpiresAt { get; set; }
+    }
+}
diff --git a/Cardiopulmonarybypasssystems/StartupPasswordWindow.xaml b/Cardiopulmonarybypasssystems/StartupPasswordWindow.xaml
new file mode 100644
index 0000000..cd009fb
--- /dev/null
+++ b/Cardiopulmonarybypasssystems/StartupPasswordWindow.xaml
@@ -0,0 +1,137 @@
+<Window x:Class="Cardiopulmonarybypasssystems.StartupPasswordWindow"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Title="系统进入验证"
+        Width="640"
+        Height="500"
+        Loaded="Window_Loaded"
+        WindowStartupLocation="CenterScreen"
+        ResizeMode="NoResize">
+    <Grid Margin="18">
+        <Border CornerRadius="22"
+                Background="#FFF7FAFB"
+                BorderBrush="#FFD7E2E6"
+                BorderThickness="1">
+            <Grid>
+                <Grid.RowDefinitions>
+                    <RowDefinition Height="126" />
+                    <RowDefinition Height="*" />
+                    <RowDefinition Height="Auto" />
+                </Grid.RowDefinitions>
+
+                <Border Grid.Row="0"
+                        CornerRadius="22,22,0,0"
+                        Padding="24,20">
+                    <Border.Background>
+                        <LinearGradientBrush StartPoint="0,0"
+                                             EndPoint="1,1">
+                            <GradientStop Color="#FF123744"
+                                          Offset="0" />
+                            <GradientStop Color="#FF0F5F75"
+                                          Offset="0.55" />
+                            <GradientStop Color="#FF2F7D7A"
+                                          Offset="1" />
+                        </LinearGradientBrush>
+                    </Border.Background>
+                    <StackPanel VerticalAlignment="Center">
+                        <TextBlock FontSize="26"
+                                   FontWeight="Bold"
+                                   Foreground="White"
+                                   Text="系统进入验证" />
+                        <Border Margin="0,10,0,0"
+                                Padding="10,6"
+                                HorizontalAlignment="Left"
+                                Background="#1FFFFFFF"
+                                CornerRadius="12">
+                            <TextBlock FontSize="12"
+                                       FontWeight="SemiBold"
+                                       Foreground="White"
+                                       Text="{Binding StageText}" />
+                        </Border>
+                    </StackPanel>
+                </Border>
+
+                <StackPanel Grid.Row="1"
+                            Margin="24,16,24,14">
+                    <Border
+                            Padding="14,10"
+                            Background="#FFEAF3F5"
+                            CornerRadius="14">
+                        <DockPanel LastChildFill="False">
+                            <StackPanel DockPanel.Dock="Left"
+                                        Orientation="Horizontal">
+                                <TextBlock FontSize="12"
+                                           Foreground="#FF52636B"
+                                           Text="到期：" />
+                                <TextBlock FontSize="13"
+                                           FontWeight="Bold"
+                                           Foreground="{StaticResource HeaderBrush}"
+                                           Text="{Binding ExpiresAtText}" />
+                            </StackPanel>
+                            <StackPanel DockPanel.Dock="Right"
+                                        Orientation="Horizontal">
+                                <TextBlock FontSize="12"
+                                           Foreground="#FF52636B"
+                                           Text="剩余：" />
+                                <TextBlock FontSize="13"
+                                           FontWeight="Bold"
+                                           Foreground="{StaticResource HeaderBrush}"
+                                           Text="{Binding RemainingText}" />
+                            </StackPanel>
+                        </DockPanel>
+                    </Border>
+
+                    <Border Margin="0,16,0,0"
+                            Padding="16"
+                            Background="White"
+                            BorderBrush="#FFDCE7EA"
+                            BorderThickness="1"
+                            CornerRadius="16">
+                        <StackPanel>
+                            <TextBlock FontSize="12"
+                                       FontWeight="SemiBold"
+                                       Foreground="{StaticResource HeaderBrush}"
+                                       Text="密码输入" />
+                            <TextBox x:Name="PasswordInput"
+                                     Margin="0,10,0,0"
+                                     MinHeight="38"
+                                     FontSize="15"
+                                     Text="{Binding PasswordText, UpdateSourceTrigger=PropertyChanged}"
+                                     TextChanged="PasswordInput_OnTextChanged" />
+                        </StackPanel>
+                    </Border>
+                </StackPanel>
+
+                <Border Grid.Row="2"
+                        Padding="18,14"
+                        Background="White"
+                        BorderBrush="#FFE2EBEE"
+                        BorderThickness="1,1,0,0"
+                        CornerRadius="0,0,22,22">
+                    <UniformGrid Columns="3">
+                        <Button Width="112"
+                                Margin="0,0,10,0"
+                                Command="{Binding CloseCommand}"
+                                CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=Window}}"
+                                Background="#FF667E88"
+                                Content="退出" />
+                        <Button Width="112"
+                                Margin="0,0,10,0"
+                                Command="{Binding ContinueCommand}"
+                                CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=Window}}"
+                                Background="#FF2B8F6A"
+                                Content="继续进入"
+                                IsEnabled="{Binding CanContinue}" />
+                        <Button Width="112"
+                                Margin="0,0,10,0"
+                                Command="{Binding SubmitCommand}"
+                                CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=Window}}"
+                                Background="#FF0F5F75"
+                                Content="提交密码"
+                                IsEnabled="{Binding CanSubmit}" />
+                    </UniformGrid>
+                </Border>
+            </Grid>
+        </Border>
+    </Grid>
+</Window>
diff --git a/Cardiopulmonarybypasssystems/StartupPasswordWindow.xaml.cs b/Cardiopulmonarybypasssystems/StartupPasswordWindow.xaml.cs
new file mode 100644
index 0000000..363d064
--- /dev/null
+++ b/Cardiopulmonarybypasssystems/StartupPasswordWindow.xaml.cs
@@ -0,0 +1,29 @@
+using System.Windows;
+using System.Windows.Input;
+using Cardiopulmonarybypasssystems.ViewModels;
+
+namespace Cardiopulmonarybypasssystems;
+
+public partial class StartupPasswordWindow : Window
+{
+    private readonly StartupPasswordViewModel _viewModel;
+
+    public StartupPasswordWindow(StartupPasswordViewModel viewModel)
+    {
+        InitializeComponent();
+        _viewModel = viewModel;
+        DataContext = viewModel;
+    }
+
+    private void Window_Loaded(object sender, RoutedEventArgs e)
+    {
+        PasswordInput.Focus();
+        Keyboard.Focus(PasswordInput);
+        PasswordInput.SelectAll();
+    }
+
+    private void PasswordInput_OnTextChanged(object sender, System.Windows.Controls.TextChangedEventArgs e)
+    {
+        _viewModel.PasswordText = PasswordInput.Text;
+    }
+}
diff --git a/Cardiopulmonarybypasssystems/ViewModels/StartupPasswordViewModel.cs b/Cardiopulmonarybypasssystems/ViewModels/StartupPasswordViewModel.cs
new file mode 100644
index 0000000..0949de4
--- /dev/null
+++ b/Cardiopulmonarybypasssystems/ViewModels/StartupPasswordViewModel.cs
@@ -0,0 +1,132 @@
+using System.Reflection;
+using System.Windows;
+using Cardiopulmonarybypasssystems.Models;
+using Cardiopulmonarybypasssystems.Services;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
+namespace Cardiopulmonarybypasssystems.ViewModels;
+
+public partial class StartupPasswordViewModel : ObservableObject
+{
+    private readonly IPasswordAccessService _passwordAccessService;
+
+    public StartupPasswordViewModel(IPasswordAccessService passwordAccessService)
+    {
+        _passwordAccessService = passwordAccessService;
+        ProductName = "心肺转流检测系统";
+        SoftwareVersion = Assembly.GetExecutingAssembly().GetName().Version?.ToString(3) ?? "1.0.0";
+        RefreshStatus();
+    }
+
+    [ObservableProperty]
+    private string productName = string.Empty;
+
+    [ObservableProperty]
+    private string softwareVersion = string.Empty;
+
+    [ObservableProperty]
+    private string passwordText = string.Empty;
+
+    [ObservableProperty]
+    private string statusTitle = string.Empty;
+
+    [ObservableProperty]
+    private string statusDetail = string.Empty;
+
+    [ObservableProperty]
+    private string stageText = string.Empty;
+
+    [ObservableProperty]
+    private string expiresAtText = "--";
+
+    [ObservableProperty]
+    private string remainingText = "--";
+
+    [ObservableProperty]
+    private string footerHint = "规则：第 1 个密码 15 天，第 2 个密码 30 天，第二次到期后自动永久有效。";
+
+    [ObservableProperty]
+    private bool canSubmit;
+
+    public bool CanContinue => _passwordAccessService.GetStatus().CanLaunch;
+
+    [RelayCommand]
+    private void Submit(Window? window)
+    {
+        if (!_passwordAccessService.TryUnlock(PasswordText, out _, out var message))
+        {
+            RefreshStatus();
+            StatusDetail = message;
+            return;
+        }
+
+        PasswordText = string.Empty;
+        RefreshStatus();
+        StatusDetail = message;
+
+        if (_passwordAccessService.GetStatus().CanLaunch && window is not null)
+        {
+            window.DialogResult = true;
+            window.Close();
+        }
+    }
+
+    [RelayCommand]
+    private void Continue(Window? window)
+    {
+        if (!_passwordAccessService.GetStatus().CanLaunch || window is null)
+        {
+            return;
+        }
+
+        window.DialogResult = true;
+        window.Close();
+    }
+
+    [RelayCommand]
+    private void Close(Window? window)
+    {
+        window?.Close();
+    }
+
+    [RelayCommand]
+    private void AppendPasswordCharacter(string? value)
+    {
+        if (string.IsNullOrEmpty(value))
+        {
+            return;
+        }
+
+        PasswordText += value;
+    }
+
+    [RelayCommand]
+    private void BackspacePassword()
+    {
+        if (string.IsNullOrEmpty(PasswordText))
+        {
+            return;
+        }
+
+        PasswordText = PasswordText[..^1];
+    }
+
+    [RelayCommand]
+    private void ClearPassword()
+    {
+        PasswordText = string.Empty;
+    }
+
+    private void RefreshStatus()
+    {
+        var status = _passwordAccessService.GetStatus();
+        StatusTitle = status.StatusTitle;
+        StatusDetail = status.StatusDetail;
+        StageText = status.StageText;
+        ExpiresAtText = status.ExpiresAt?.ToString("yyyy-MM-dd HH:mm") ?? (status.IsPermanent ? "永久有效" : "--");
+        RemainingText = status.IsPermanent ? "永久" : status.RemainingDays > 0 ? $"{status.RemainingDays} 天" : "需输入密码";
+        CanSubmit = status.CanSubmitPassword;
+        OnPropertyChanged(nameof(CanContinue));
+    }
+}