diff --git a/include/rtdef.h b/include/rtdef.h
index 34bb283ae7..0d5c421759 100644
--- a/include/rtdef.h
+++ b/include/rtdef.h
@@ -117,7 +117,7 @@ extern "C" {
 
 /* Common Utilities */
 
-#define RT_UNUSED(x)                   ((void)x)
+#define RT_UNUSED(x)                   ((void)(x))
 
 /* compile time assertion */
 #define RT_STATIC_ASSERT(name, expn) typedef char _static_assert_##name[(expn)?1:-1]
diff --git a/include/rtthread.h b/include/rtthread.h
index 311516bd8b..e6740d46da 100644
--- a/include/rtthread.h
+++ b/include/rtthread.h
@@ -804,7 +804,7 @@ if (!(EX))                                                                    \
     rt_assert_handler(#EX, __FUNCTION__, __LINE__);                           \
 }
 #else
-#define RT_ASSERT(EX)
+#define RT_ASSERT(EX) {RT_UNUSED(EX);}
 #endif /* RT_DEBUGING_ASSERT */
 
 #ifdef RT_DEBUGING_CONTEXT