diff --git a/kal/cmsis/cmsis_liteos2.c b/kal/cmsis/cmsis_liteos2.c
index 4c741240..9aa795b6 100644
--- a/kal/cmsis/cmsis_liteos2.c
+++ b/kal/cmsis/cmsis_liteos2.c
@@ -639,7 +639,7 @@ osStatus_t osDelay(uint32_t ticks)
         return osOK;
     }
     if (osKernelGetState() != osKernelRunning) {
-        HalDelay(ticks);
+        LOS_UDelay(ticks * OS_US_PER_TICK);
     } else {
         uwRet = LOS_TaskDelay(ticks);
     }
diff --git a/kernel/arch/include/los_timer.h b/kernel/arch/include/los_timer.h
index bc09a703..498f02c4 100644
--- a/kernel/arch/include/los_timer.h
+++ b/kernel/arch/include/los_timer.h
@@ -67,9 +67,7 @@ VOID HalClearSysSleepFlag(VOID);
 
 VOID HalEnterSleep(LOS_SysSleepEnum sleep);
 
-VOID HalDelay(UINT32 ticks);
-
- /**
+/**
  * @ingroup los_timer
  * @brief Get systick cycle.
  *
diff --git a/kernel/include/los_task.h b/kernel/include/los_task.h
index aae6d7d9..d1288f5a 100644
--- a/kernel/include/los_task.h
+++ b/kernel/include/los_task.h
@@ -1088,25 +1088,24 @@ extern  UINT32 LOS_NewTaskIDGet(VOID);
   */
 extern CHAR* LOS_TaskNameGet(UINT32 taskID);
 
-
 /* *
- * @ingroup  los_hw
- * @brief: Function to determine whether task scheduling is required.
+ * @ingroup  los_task
+ * @brief: cpu delay.
  *
  * @par Description:
- * This API is used to Judge and entry task scheduling.
+ * This API is used to cpu delay, no task switching.
  *
  * @attention:
  * <ul><li>None.</li></ul>
  *
- * @param  None.
+ * @param  UINT64  [IN] delay times, microseconds.
  *
  * @retval: None.
  * @par Dependency:
- * <ul><li>los_hw.h: the header file that contains the API declaration.</li></ul>
+ * <ul><li>los_task.h: the header file that contains the API declaration.</li></ul>
  * @see None.
  */
-extern VOID LOS_Schedule(VOID);
+extern VOID LOS_UDelay(UINT64 microseconds);
 
 /**
 * @ingroup los_cpup
diff --git a/kernel/src/los_task.c b/kernel/src/los_task.c
index 8c226c34..89561b0a 100644
--- a/kernel/src/los_task.c
+++ b/kernel/src/los_task.c
@@ -1296,3 +1296,19 @@ LITE_OS_SEC_TEXT_MINOR VOID LOS_Msleep(UINT32 mSecs)
     (VOID)LOS_TaskDelay(interval);
 }
 
+VOID LOS_UDelay(UINT64 microseconds)
+{
+    UINT64 endTime;
+
+    if (microseconds == 0) {
+        return;
+    }
+
+    endTime = (microseconds / OS_SYS_US_PER_SECOND) * OS_SYS_CLOCK +
+            (microseconds % OS_SYS_US_PER_SECOND) * OS_SYS_CLOCK / OS_SYS_US_PER_SECOND;
+    endTime = LOS_SysCycleGet() + endTime;
+    while (LOS_SysCycleGet() < endTime) {
+    }
+
+    return;
+}