diff --git a/include/rtservice.h b/include/rtservice.h
index d0bad85de1..1524af10f7 100644
--- a/include/rtservice.h
+++ b/include/rtservice.h
@@ -27,8 +27,8 @@ extern "C" {
 /**@{*/
 
 /**
- * rt_container_of - return the member address of ptr, if the type of ptr is the
- * struct type.
+ * rt_container_of - return the start address of struct type, while ptr is the
+ * member of struct type.
  */
 #define rt_container_of(ptr, type, member) \
     ((type *)((char *)(ptr) - (unsigned long)(&((type *)0)->member)))