diff --git a/components/libc/armlibc/sys/unistd.h b/components/libc/armlibc/sys/unistd.h
index 06a46746c0549a85f00e2bc813fc6801bf1657c0..e1e0dc904c90025d681f7e24a0eaf7a56a8ec46d 100644
--- a/components/libc/armlibc/sys/unistd.h
+++ b/components/libc/armlibc/sys/unistd.h
@@ -1,6 +1,8 @@
 #ifndef _SYS_UNISTD_H
 #define _SYS_UNISTD_H
 
+#include <rtthread.h>
+
 #ifdef RT_USING_DFS
 #include <dfs_posix.h>
 #else