diff --git a/stopwatch/stopwatch.go b/stopwatch/stopwatch.go
index b49681b..a493a6b 100644
--- a/stopwatch/stopwatch.go
+++ b/stopwatch/stopwatch.go
@@ -2,11 +2,13 @@ package stopwatch
 
 import (
 	"time"
+
+	_ "unsafe"
 )
 
 type watch struct {
-	startTime time.Time
-	elapsed   time.Duration
+	startTime int64
+	elapsed   int64
 	isRunning bool
 }
 
@@ -19,7 +21,7 @@ func StartNew() *watch {
 
 func (w *watch) Start() {
 	if !w.isRunning {
-		w.startTime = time.Now()
+		w.startTime = runtimeNano()
 		w.isRunning = true
 	}
 }
@@ -27,20 +29,21 @@ func (w *watch) Start() {
 // 将运行时间重置为零，并开始测量运行时间。
 func (w *watch) Restart() {
 	w.elapsed = 0
-	w.startTime = time.Now()
+	w.startTime = runtimeNano()
 	w.isRunning = true
 }
 
 // 停止时间间隔测量并将经过的时间重置为零。
 func (w *watch) Reset() {
 	w.elapsed = 0
-	w.startTime = time.Now()
+	w.startTime = runtimeNano()
 	w.isRunning = false
 }
 
 func (w *watch) Stop() {
 	if w.isRunning {
-		num := time.Since(w.startTime)
+		n := runtimeNano()
+		num := n - w.startTime
 		w.elapsed += num
 		w.isRunning = false
 
@@ -67,10 +70,14 @@ func (w *watch) ElapsedMicroseconds() int64 {
 }
 
 func (w *watch) ElapsedNanoseconds() int64 {
+	now := runtimeNano()
 	num := w.elapsed
 	if w.isRunning {
-		num += time.Since(w.startTime)
+		num += now - w.startTime
 	}
 
-	return num.Nanoseconds()
+	return num
 }
+
+//go:linkname runtimeNano runtime.nanotime
+func runtimeNano() int64
diff --git a/stopwatch/stopwatch_test.go b/stopwatch/stopwatch_test.go
index e267915..6ada7d6 100644
--- a/stopwatch/stopwatch_test.go
+++ b/stopwatch/stopwatch_test.go
@@ -3,6 +3,7 @@ package stopwatch_test
 import (
 	"testing"
 	"time"
+	_ "unsafe"
 
 	"github.com/charlienet/go-mixed/stopwatch"
 )
@@ -28,3 +29,16 @@ func TestWatch(t *testing.T) {
 
 	watch.Restart()
 }
+
+func TestStop(t *testing.T) {
+	watch := stopwatch.StartNew()
+	time.Sleep(time.Second)
+
+	watch.Stop()
+	time.Sleep(time.Second)
+	watch.Start()
+
+	time.Sleep(time.Second)
+
+	t.Log(watch.Elapsed())
+}