diff --git a/src/BootstrapBlazor/Components/Timer/Timer.razor b/src/BootstrapBlazor/Components/Timer/Timer.razor
index ffc51e67463e3becaa8db921cad936b354395650..f36ac98ff776fa3cdfc8a11e708a9740aa1a17be 100644
--- a/src/BootstrapBlazor/Components/Timer/Timer.razor
+++ b/src/BootstrapBlazor/Components/Timer/Timer.razor
@@ -19,6 +19,6 @@
     }
     else
     {
-        <TimePickerBody @bind-Value="@Value" OnConfirm="@OnStart" ConfirmText="@StarText" />
+        <TimePickerBody @bind-Value="@Value" OnConfirm="@OnStart" ConfirmButtonText="@StarText" />
     }
-</div>
\ No newline at end of file
+</div>
diff --git a/src/BootstrapBlazor/Components/Timer/Timer.razor.cs b/src/BootstrapBlazor/Components/Timer/Timer.razor.cs
index 0fc64c911bc89244525a6ba04fe4c0973fbaff3d..c9d1ad3d1e9cde1b0b62b7f1a12dbd515183ca6b 100644
--- a/src/BootstrapBlazor/Components/Timer/Timer.razor.cs
+++ b/src/BootstrapBlazor/Components/Timer/Timer.razor.cs
@@ -42,7 +42,7 @@ public partial class Timer : IDisposable
 
     private CancellationTokenSource? CancelTokenSource { get; set; }
 
-    private ManualResetEvent ResetEvent { get; set; } = new(true);
+    private ManualResetEvent ResetEvent { get; } = new(true);
 
     private bool Vibrate { get; set; }
 
@@ -153,44 +153,49 @@ public partial class Timer : IDisposable
 
         Task.Run(async () =>
         {
+            // 点击 Cancel 后重新设置再点击 Star
             if (CancelTokenSource != null)
             {
+                CancelTokenSource.Cancel();
                 CancelTokenSource.Dispose();
             }
 
             CancelTokenSource = new CancellationTokenSource();
 
-            try
+            do
             {
-                do
+                try
                 {
-                    await Task.Delay(1000, CancelTokenSource?.Token ?? new CancellationToken(true));
+                    await Task.Delay(1000, CancelTokenSource.Token);
+                }
+                catch (TaskCanceledException) { }
 
-                    if (!(CancelTokenSource?.IsCancellationRequested ?? true))
-                    {
-                        ResetEvent.WaitOne();
-                        CurrentTimespan = CurrentTimespan.Subtract(TimeSpan.FromSeconds(1));
-                        await InvokeAsync(StateHasChanged);
-                    }
+                if (!CancelTokenSource.IsCancellationRequested)
+                {
+                    ResetEvent.WaitOne();
+                    CurrentTimespan = CurrentTimespan.Subtract(TimeSpan.FromSeconds(1));
+                    await InvokeAsync(StateHasChanged);
                 }
-                while (!(CancelTokenSource?.IsCancellationRequested ?? true) && CurrentTimespan > TimeSpan.Zero);
+            }
+            while (!CancelTokenSource.IsCancellationRequested && CurrentTimespan > TimeSpan.Zero);
 
-                if (CurrentTimespan == TimeSpan.Zero)
+            if (CurrentTimespan == TimeSpan.Zero)
+            {
+                await Task.Delay(500, CancelTokenSource.Token);
+                if (!CancelTokenSource.IsCancellationRequested)
                 {
-                    await Task.Delay(500, CancelTokenSource?.Token ?? new CancellationToken(true));
-                    if (!(CancelTokenSource?.IsCancellationRequested ?? true))
+                    Value = TimeSpan.Zero;
+                    await InvokeAsync(() =>
                     {
-                        Value = TimeSpan.Zero;
-                        await InvokeAsync(() =>
+                        Vibrate = IsVibrate;
+                        StateHasChanged();
+                        if (OnTimeout != null)
                         {
-                            Vibrate = IsVibrate;
-                            StateHasChanged();
-                            OnTimeout?.Invoke();
-                        });
-                    }
+                            OnTimeout();
+                        }
+                    });
                 }
             }
-            catch (TaskCanceledException) { }
         });
     }
 
@@ -214,8 +219,14 @@ public partial class Timer : IDisposable
     private async Task OnClickCancel()
     {
         Value = TimeSpan.Zero;
-        CancelTokenSource?.Cancel();
-        if (OnCancel != null) await OnCancel.Invoke();
+        if (CancelTokenSource != null)
+        {
+            CancelTokenSource.Cancel();
+        }
+        if (OnCancel != null)
+        {
+            await OnCancel();
+        }
     }
 
     /// <summary>
@@ -226,9 +237,12 @@ public partial class Timer : IDisposable
     {
         if (disposing)
         {
-            CancelTokenSource?.Dispose();
-            CancelTokenSource = null;
-
+            if (CancelTokenSource != null)
+            {
+                CancelTokenSource.Cancel();
+                CancelTokenSource.Dispose();
+                CancelTokenSource = null;
+            }
             ResetEvent.Dispose();
         }
     }
diff --git a/test/UnitTest/Components/TimerTest.cs b/test/UnitTest/Components/TimerTest.cs
new file mode 100644
index 0000000000000000000000000000000000000000..26ed13a9e9603ceadd423f3df3c382f97ad440a0
--- /dev/null
+++ b/test/UnitTest/Components/TimerTest.cs
@@ -0,0 +1,147 @@
+// Copyright (c) Argo Zhang (argo@163.com). All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+// Website: https://www.blazor.zone or https://argozhang.github.io/
+
+using System.Threading;
+using Timer = BootstrapBlazor.Components.Timer;
+
+namespace UnitTest.Components;
+
+public class TimerTest : BootstrapBlazorTestBase
+{
+    [Fact]
+    public void Value_Ok()
+    {
+        var cut = Context.RenderComponent<Timer>(builder => builder.Add(a => a.Value, TimeSpan.FromSeconds(10)));
+
+        Assert.Contains("circle-body", cut.Markup);
+
+        cut.SetParametersAndRender(pb =>
+        {
+            pb.Add(a => a.Value, TimeSpan.Zero);
+        });
+        Assert.DoesNotContain("circle-body", cut.Markup);
+    }
+
+    [Fact]
+    public void Width_Ok()
+    {
+        var cut = Context.RenderComponent<Timer>(builder =>
+        {
+            builder.Add(a => a.Value, TimeSpan.FromSeconds(5));
+            builder.Add(a => a.Width, 100);
+        });
+
+        Assert.Contains("width: 100px", cut.Markup);
+    }
+
+    [Fact]
+    public void StrokeWidth_Ok()
+    {
+        var cut = Context.RenderComponent<Timer>(pb =>
+        {
+            pb.Add(a => a.Value, TimeSpan.FromSeconds(5));
+            pb.Add(a => a.StrokeWidth, 5);
+        });
+        Assert.Contains("stroke-width=\"5\"", cut.Markup);
+
+        // 增加代码覆盖率
+        //Width / 2 < StrokeWidth
+        cut.SetParametersAndRender(pb =>
+        {
+            pb.Add(a => a.Width, 6);
+            pb.Add(a => a.StrokeWidth, 6);
+        });
+        Assert.Equal(2, cut.Instance.StrokeWidth);
+    }
+
+    [Fact]
+    public void Color_Ok()
+    {
+        var cut = Context.RenderComponent<Timer>(pb =>
+        {
+            pb.Add(a => a.Value, TimeSpan.FromSeconds(5));
+            pb.Add(a => a.Color, Color.Success);
+        });
+        Assert.Contains("circle-success", cut.Markup);
+    }
+
+    [Fact]
+    public void ShowProgress_Ok()
+    {
+        var cut = Context.RenderComponent<Timer>(pb =>
+        {
+            pb.Add(a => a.Value, TimeSpan.FromSeconds(5));
+            pb.Add(a => a.ShowProgress, false);
+        });
+        Assert.Contains("circle-title d-none", cut.Markup);
+    }
+
+    [Fact]
+    public void IsVibrate_Ok()
+    {
+        var cut = Context.RenderComponent<Timer>(pb =>
+        {
+            pb.Add(a => a.Value, TimeSpan.FromSeconds(5));
+            pb.Add(a => a.IsVibrate, false);
+        });
+    }
+
+    [Fact]
+    public async Task OnStart_Ok()
+    {
+        var timeout = false;
+        var cut = Context.RenderComponent<Timer>(pb =>
+        {
+            pb.Add(a => a.OnTimeout, () =>
+            {
+                timeout = true;
+                return Task.CompletedTask;
+            });
+        });
+        var downs = cut.FindAll(".time-spinner-arrow.fa-angle-down");
+        downs[2].Click();
+        cut.Find(".time-panel-btn.confirm").Click();
+
+        await Task.Delay(2000);
+        Assert.True(timeout);
+    }
+
+    [Fact]
+    public async Task OnCancel_Ok()
+    {
+        var cancelled = false;
+        var cut = Context.RenderComponent<Timer>(pb =>
+        {
+            pb.Add(a => a.OnCancel, () =>
+            {
+                cancelled = true;
+                return Task.CompletedTask;
+            });
+        });
+        var downs = cut.FindAll(".time-spinner-arrow.fa-angle-down");
+        downs[0].Click();
+        cut.Find(".time-panel-btn.confirm").Click();
+        await Task.Delay(1000);
+        var buttons = cut.FindAll(".timer-buttons button");
+        // pause
+        Assert.True(buttons[1].ClassList.Contains("btn-warning"));
+        buttons[1].Click();
+
+        // resume
+        buttons = cut.FindAll(".timer-buttons button");
+        Assert.True(buttons[1].ClassList.Contains("btn-success"));
+        buttons[1].Click();
+
+        // cancel
+        buttons = cut.FindAll(".timer-buttons button");
+        buttons[0].Click();
+        Assert.True(cancelled);
+
+        // 代码覆盖率 Cancel 后再 Star
+        downs = cut.FindAll(".time-spinner-arrow.fa-angle-down");
+        downs[0].Click();
+        cut.Find(".time-panel-btn.confirm").Click();
+        await Task.Delay(1000);
+    }
+}