diff --git a/include/rtthread.h b/include/rtthread.h
index 0e98753c6f669e78b352fefe2b427ae2f8632b53..dbb9879af3a5ec97b648fe60658ed5458b783d6e 100644
--- a/include/rtthread.h
+++ b/include/rtthread.h
@@ -120,6 +120,7 @@ void rt_thread_idle_init(void);
 #ifdef RT_USING_HOOK
 void rt_thread_idle_sethook(void (*hook)(void));
 #endif
+void rt_thread_idle_excute(void);
 
 /*
  * schedule service
diff --git a/src/idle.c b/src/idle.c
index f750a816015549582d3f71d9c4dc0081c3377570..fcd6e457e2fb4b3463e263c6a80ff32b79911c28 100644
--- a/src/idle.c
+++ b/src/idle.c
@@ -52,61 +52,88 @@ void rt_thread_idle_sethook(void (*hook)())
 /*@}*/
 #endif
 
-static void rt_thread_idle_entry(void* parameter)
+/**
+ * This function will do some things when system idle.
+ */
+void rt_thread_idle_excute(void)
 {
-	while (1)
+#ifdef RT_USING_HEAP
+	/* check the defunct thread list */
+	if (!rt_list_isempty(&rt_thread_defunct))
 	{
-#ifdef RT_USING_HOOK
-		/* if there is an idle thread hook */
-		if (rt_thread_idle_hook != RT_NULL) rt_thread_idle_hook();
+		rt_base_t lock;
+		rt_thread_t thread;
+#ifdef RT_USING_MODULE
+		rt_module_t module;
 #endif
 
-#ifdef RT_USING_HEAP
-		/* check the defunct thread list */
+		/* disable interrupt */
+		lock = rt_hw_interrupt_disable();
+
+		/* re-check whether list is empty */
 		if (!rt_list_isempty(&rt_thread_defunct))
 		{
-			rt_base_t lock;
-			struct rt_thread* thread = rt_list_entry(rt_thread_defunct.next, struct rt_thread, tlist);
+			/* get defunct thread */
+			thread = rt_list_entry(rt_thread_defunct.next, struct rt_thread, tlist);
+
+			/* get thread's parent module */
 #ifdef RT_USING_MODULE
-			rt_module_t module = thread->module_parent;
+			module = thread->module_parent;
 #endif
-
-			/* disable interrupt */
-			lock = rt_hw_interrupt_disable();
-
+			/* remove defunct thread */
 			rt_list_remove(&(thread->tlist));
-
+		}
+		else
+		{
 			/* enable interrupt */
 			rt_hw_interrupt_enable(lock);
 
-			/* release thread's stack */
-			rt_free(thread->stack_addr);
+			/* may the defunct thread list is removed by others, just return */
+			return;
+		}
 
-			/* delete thread object */
-			rt_object_delete((rt_object_t)thread);
+		/* enable interrupt */
+		rt_hw_interrupt_enable(lock);
 
 #ifdef RT_USING_MODULE
-			if(module != RT_NULL)
+		if(module != RT_NULL)
+		{	
+			/* if the thread is module's main thread */
+			if(module->module_thread == thread)
 			{	
-				/* if the thread is module's main thread */
-				if(module->module_thread == thread)
-				{	
-					/* detach module's main thread */
-					module->module_thread = RT_NULL;
-				}
-
-				/* if sub thread list and main thread are null */
-				if((module->module_thread == RT_NULL) &&
-					rt_list_isempty(&module->module_object[RT_Object_Class_Thread].object_list) &&
-					(module->module_info->module_type == RT_Module_Class_APP))
-				{
-					/* unload module */
-					rt_module_unload(module);
-				}						
-			}	
+				/* detach module's main thread */
+				module->module_thread = RT_NULL;
+			}
+
+			/* if sub thread list and main thread are null */
+			if((module->module_thread == RT_NULL) &&
+				rt_list_isempty(&module->module_object[RT_Object_Class_Thread].object_list) &&
+				(module->module_info->module_type == RT_Module_Class_APP))
+			{
+				/* unload module */
+				rt_module_unload(module);
+			}						
+		}	
 #endif
-		}
+		/* release thread's stack */
+		rt_free(thread->stack_addr);
+
+		/* delete thread object */
+		rt_object_delete((rt_object_t)thread);
+	}
+#endif
+}
+
+static void rt_thread_idle_entry(void* parameter)
+{
+	while (1)
+	{
+#ifdef RT_USING_HOOK
+		/* if there is an idle thread hook */
+		if (rt_thread_idle_hook != RT_NULL) rt_thread_idle_hook();
 #endif
+
+		rt_thread_idle_excute();
 	}
 }