diff --git a/bsp/lpc824/rtconfig.h b/bsp/lpc824/rtconfig.h
index b51d38aa9a..1426427b8d 100644
--- a/bsp/lpc824/rtconfig.h
+++ b/bsp/lpc824/rtconfig.h
@@ -80,7 +80,7 @@
 // </c>
 // <c1>Using Mutex
 //  <i>Using Mutex
-//#define RT_USING_MUTEX
+#define RT_USING_MUTEX
 // </c>
 // <c1>Using Event
 //  <i>Using Event