diff --git a/klock.go b/klock.go
index ac47526..d6a5395 100644
--- a/klock.go
+++ b/klock.go
@@ -185,6 +185,7 @@ func (kl *KeyLock) TryLock(key string) bool {
 // LockWithTimeout 尝试在给定的时间内为指定的键获取写锁。
 // 如果在超时前成功获取锁，则返回 true；否则返回 false。
 func (kl *KeyLock) LockWithTimeout(key string, timeout time.Duration) bool {
+	deadline := time.Now().Add(timeout)
 	le := kl.prepareLock(key)
 	// 立即尝试一次，以避免在锁可用时产生不必要的延迟。
 	if le.rw.TryLock() {
@@ -197,25 +198,33 @@ func (kl *KeyLock) LockWithTimeout(key string, timeout time.Duration) bool {
 			kl.cancelLock(key, le)
 		}
 	}()
-	timer := time.NewTimer(timeout)
-	defer timer.Stop()
 	pollInterval := kl.config.InitialPollInterval
 	maxPollInterval := kl.config.MaxPollInterval
 	for {
-		select {
-		case <-timer.C:
+		remaining := time.Until(deadline)
+		if remaining <= 0 {
 			return false
-		default:
-			time.Sleep(pollInterval)
-			if le.rw.TryLock() {
-				kl.commitLock(key, le)
-				acquired = true
-				return true
-			}
-			pollInterval *= 2
-			if pollInterval > maxPollInterval {
-				pollInterval = maxPollInterval
+		}
+		sleepInterval := pollInterval
+		if sleepInterval > remaining {
+			sleepInterval = remaining
+		}
+		time.Sleep(sleepInterval)
+		if time.Until(deadline) <= 0 {
+			return false
+		}
+		if le.rw.TryLock() {
+			if time.Until(deadline) <= 0 {
+				le.rw.Unlock()
+				return false
 			}
+			kl.commitLock(key, le)
+			acquired = true
+			return true
+		}
+		pollInterval *= 2
+		if pollInterval > maxPollInterval {
+			pollInterval = maxPollInterval
 		}
 	}
 }
@@ -244,6 +253,7 @@ func (kl *KeyLock) TryRLock(key string) bool {
 // RLockWithTimeout 尝试在给定的时间内为指定的键获取读锁。
 // 如果在超时前成功获取锁，则返回 true；否则返回 false。
 func (kl *KeyLock) RLockWithTimeout(key string, timeout time.Duration) bool {
+	deadline := time.Now().Add(timeout)
 	le := kl.prepareLock(key)
 	// 立即尝试一次
 	if le.rw.TryRLock() {
@@ -256,25 +266,33 @@ func (kl *KeyLock) RLockWithTimeout(key string, timeout time.Duration) bool {
 			kl.cancelLock(key, le)
 		}
 	}()
-	timer := time.NewTimer(timeout)
-	defer timer.Stop()
 	pollInterval := kl.config.InitialPollInterval
 	maxPollInterval := kl.config.MaxPollInterval
 	for {
-		select {
-		case <-timer.C:
+		remaining := time.Until(deadline)
+		if remaining <= 0 {
 			return false
-		default:
-			time.Sleep(pollInterval)
-			if le.rw.TryRLock() {
-				kl.commitLock(key, le)
-				acquired = true
-				return true
-			}
-			pollInterval *= 2
-			if pollInterval > maxPollInterval {
-				pollInterval = maxPollInterval
+		}
+		sleepInterval := pollInterval
+		if sleepInterval > remaining {
+			sleepInterval = remaining
+		}
+		time.Sleep(sleepInterval)
+		if time.Until(deadline) <= 0 {
+			return false
+		}
+		if le.rw.TryRLock() {
+			if time.Until(deadline) <= 0 {
+				le.rw.RUnlock()
+				return false
 			}
+			kl.commitLock(key, le)
+			acquired = true
+			return true
+		}
+		pollInterval *= 2
+		if pollInterval > maxPollInterval {
+			pollInterval = maxPollInterval
 		}
 	}
 }
diff --git a/klock_test.go b/klock_test.go
index 3114f0f..a5a7b5c 100644
--- a/klock_test.go
+++ b/klock_test.go
@@ -250,6 +250,30 @@ func TestLockWithTimeout(t *testing.T) {
 	}
 }
 
+// TestLockWithTimeoutDoesNotAcquireAfterDeadline 测试写锁在超时后被释放时不会再被获取。
+func TestLockWithTimeoutDoesNotAcquireAfterDeadline(t *testing.T) {
+	kl := NewWithConfig(Config{
+		MaxPollInterval:     50 * time.Millisecond,
+		InitialPollInterval: 50 * time.Millisecond,
+	})
+	key := "test_key"
+	released := make(chan struct{})
+	kl.Lock(key)
+	go func() {
+		time.Sleep(20 * time.Millisecond)
+		kl.Unlock(key)
+		close(released)
+	}()
+	acquired := kl.LockWithTimeout(key, 10*time.Millisecond)
+	if acquired {
+		kl.Unlock(key)
+	}
+	<-released
+	if acquired {
+		t.Fatal("LockWithTimeout 不应该在超时后获取锁")
+	}
+}
+
 // TestRLockWithTimeout 测试带超时的读锁获取功能。
 func TestRLockWithTimeout(t *testing.T) {
 	kl := New()
@@ -270,6 +294,30 @@ func TestRLockWithTimeout(t *testing.T) {
 	}
 }
 
+// TestRLockWithTimeoutDoesNotAcquireAfterDeadline 测试读锁在超时后被释放时不会再被获取。
+func TestRLockWithTimeoutDoesNotAcquireAfterDeadline(t *testing.T) {
+	kl := NewWithConfig(Config{
+		MaxPollInterval:     50 * time.Millisecond,
+		InitialPollInterval: 50 * time.Millisecond,
+	})
+	key := "test_key"
+	released := make(chan struct{})
+	kl.Lock(key)
+	go func() {
+		time.Sleep(20 * time.Millisecond)
+		kl.Unlock(key)
+		close(released)
+	}()
+	acquired := kl.RLockWithTimeout(key, 10*time.Millisecond)
+	if acquired {
+		kl.RUnlock(key)
+	}
+	<-released
+	if acquired {
+		t.Fatal("RLockWithTimeout 不应该在超时后获取锁")
+	}
+}
+
 // TestPanicOnUnlockOfUnlockedKey 测试对未锁定的键执行 Unlock 操作是否会引发 panic。
 func TestPanicOnUnlockOfUnlockedKey(t *testing.T) {
 	defer func() {