diff --git a/TodoList/ViewModels/MainViewModel.cs b/TodoList/ViewModels/MainViewModel.cs
index e102e9c..c0afc50 100644
--- a/TodoList/ViewModels/MainViewModel.cs
+++ b/TodoList/ViewModels/MainViewModel.cs
@@ -25,6 +25,18 @@ namespace TodoList.ViewModels
 
         [ObservableProperty]
         private TodoPriority newPriority = TodoPriority.Medium;
+
+        [ObservableProperty]
+        private bool isEditDialogOpen;
+
+        [ObservableProperty]
+        private TodoItem editingTask;
+
+        [ObservableProperty]
+        private string editContent;
+
+        [ObservableProperty]
+        private TodoPriority editPriority = TodoPriority.Medium;
         
         [ObservableProperty]
         private bool isSettingsOpen;
@@ -189,6 +201,39 @@ namespace TodoList.ViewModels
             Tasks.Remove(item);
         }
 
+        [RelayCommand]
+        private void OpenEditDialog(TodoItem item)
+        {
+            if (item == null) return;
+            EditingTask = item;
+            EditContent = item.Content;
+            EditPriority = item.Priority;
+            IsEditDialogOpen = true;
+        }
+
+        [RelayCommand]
+        private void CloseEditDialog()
+        {
+            IsEditDialogOpen = false;
+            EditingTask = null;
+            EditContent = string.Empty;
+            EditPriority = TodoPriority.Medium;
+        }
+
+        [RelayCommand]
+        private async Task SaveEditAsync()
+        {
+            if (EditingTask == null || string.IsNullOrWhiteSpace(EditContent)) return;
+
+            EditingTask.Content = EditContent;
+            EditingTask.Priority = EditPriority;
+            EditingTask.SyncStatus = SyncStatus.Pending;
+
+            await _dataService.SaveTaskAsync(EditingTask);
+            await LoadTasksAsync();
+            CloseEditDialog();
+        }
+
         public async void Receive(TaskAddedMessage message)
         {
             await LoadTasksAsync();
diff --git a/TodoList/Views/MainWindow.xaml b/TodoList/Views/MainWindow.xaml
index 1558cea..eee2043 100644
--- a/TodoList/Views/MainWindow.xaml
+++ b/TodoList/Views/MainWindow.xaml
@@ -172,6 +172,7 @@
                     <Setter Property="Background" Value="White"/>
                     <Setter Property="Margin" Value="0,0,0,10"/>
                     <Setter Property="Padding" Value="10"/>
+                    <EventSetter Event="MouseDoubleClick" Handler="ListBoxItem_MouseDoubleClick"/>
                     <Setter Property="Template">
                         <Setter.Value>
                             <ControlTemplate TargetType="ListBoxItem">
@@ -232,6 +233,27 @@
                             <TextBlock Text="{Binding Priority, Converter={StaticResource EnumDescConverter}}" FontSize="12" Foreground="#888" Margin="0,2,0,0"/>
                         </StackPanel>
 
+                        <Button Grid.Column="2" Content="✎" 
+                                Command="{Binding DataContext.OpenEditDialogCommand, RelativeSource={RelativeSource AncestorType=Window}}"
+                                CommandParameter="{Binding}"
+                                Width="24" Height="24" 
+                                Background="Transparent" Foreground="#007AFF" 
+                                BorderThickness="0" FontSize="12" FontWeight="Bold"
+                                Cursor="Hand" Margin="0,0,5,0">
+                            <Button.Template>
+                                <ControlTemplate TargetType="Button">
+                                    <Border x:Name="border" Background="{TemplateBinding Background}" CornerRadius="12">
+                                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                                    </Border>
+                                    <ControlTemplate.Triggers>
+                                        <Trigger Property="IsMouseOver" Value="True">
+                                            <Setter TargetName="border" Property="Background" Value="#1A007AFF"/>
+                                        </Trigger>
+                                    </ControlTemplate.Triggers>
+                                </ControlTemplate>
+                            </Button.Template>
+                        </Button>
+
                         <Button Grid.Column="3" Content="✕" 
                                 Command="{Binding DataContext.DeleteCommand, RelativeSource={RelativeSource AncestorType=Window}}"
                                 CommandParameter="{Binding}"
@@ -301,5 +323,52 @@
                 </Grid>
             </Border>
         </Grid>
+
+        <!-- Edit Dialog Overlay -->
+        <Grid Grid.RowSpan="3" Background="#80000000" Visibility="{Binding IsEditDialogOpen, Converter={StaticResource BoolToVis}}">
+            <Border Background="White" Width="350" Height="250" CornerRadius="10" VerticalAlignment="Center" HorizontalAlignment="Center" Padding="20">
+                <Grid>
+                    <Grid.RowDefinitions>
+                        <RowDefinition Height="Auto"/>
+                        <RowDefinition Height="*"/>
+                        <RowDefinition Height="Auto"/>
+                    </Grid.RowDefinitions>
+                    
+                    <TextBlock Text="编辑任务" FontSize="18" FontWeight="Bold" HorizontalAlignment="Center" Margin="0,0,0,15"/>
+                    
+                    <StackPanel Grid.Row="1" VerticalAlignment="Center">
+                        <TextBlock Text="任务内容" Foreground="#666" Margin="0,0,0,5" FontSize="12"/>
+                        <TextBox Text="{Binding EditContent, UpdateSourceTrigger=PropertyChanged}" 
+                                 FontSize="14" Padding="8" Margin="0,0,0,15" BorderThickness="1" BorderBrush="#DDD"
+                                 VerticalContentAlignment="Center"/>
+                        
+                        <TextBlock Text="优先级" Foreground="#666" Margin="0,0,0,5" FontSize="12"/>
+                        <ComboBox ItemsSource="{Binding Source={StaticResource PriorityEnum}}"
+                                  SelectedItem="{Binding EditPriority}"
+                                  Width="300" VerticalContentAlignment="Center" BorderThickness="1" BorderBrush="#DDD">
+                            <ComboBox.ItemTemplate>
+                                <DataTemplate>
+                                    <TextBlock Text="{Binding Converter={StaticResource EnumDescConverter}}"/>
+                                </DataTemplate>
+                            </ComboBox.ItemTemplate>
+                        </ComboBox>
+                    </StackPanel>
+                    
+                    <StackPanel Grid.Row="2" Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,15,0,0">
+                        <Button Content="取消" Command="{Binding CloseEditDialogCommand}" Width="80" Margin="0,0,10,0"
+                                Background="#EEE" Foreground="#333" Height="30" BorderThickness="0">
+                             <Button.Template>
+                                <ControlTemplate TargetType="Button">
+                                    <Border Background="{TemplateBinding Background}" CornerRadius="5">
+                                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
+                                    </Border>
+                                </ControlTemplate>
+                            </Button.Template>
+                        </Button>
+                        <Button Content="保存" Command="{Binding SaveEditCommand}" Width="80" Height="30" Style="{StaticResource ModernButton}"/>
+                    </StackPanel>
+                </Grid>
+            </Border>
+        </Grid>
     </Grid>
 </Window>
diff --git a/TodoList/Views/MainWindow.xaml.cs b/TodoList/Views/MainWindow.xaml.cs
index 83623db..ec9b719 100644
--- a/TodoList/Views/MainWindow.xaml.cs
+++ b/TodoList/Views/MainWindow.xaml.cs
@@ -1,4 +1,5 @@
 using System.Windows;
+using System.Windows.Controls;
 using System.Windows.Input;
 using TodoList.ViewModels;
 
@@ -77,5 +78,13 @@ namespace TodoList.Views
                 vm.ShortcutKey = keyStr;
             }
         }
+
+        private void ListBoxItem_MouseDoubleClick(object sender, MouseButtonEventArgs e)
+        {
+            if (sender is ListBoxItem item && item.DataContext is Models.TodoItem todoItem && DataContext is MainViewModel vm)
+            {
+                vm.OpenEditDialogCommand.Execute(todoItem);
+            }
+        }
     }
 }