diff --git a/src/SConscript b/src/SConscript
index 82c3b8aaf1b5435709a35175ad9e881718902f58..c03d997cd1f27e008ed3ad34d72ffe3b747bfb10 100644
--- a/src/SConscript
+++ b/src/SConscript
@@ -29,6 +29,8 @@ if GetDepend('RT_USING_DEVICE') == False:
 if GetDepend('RT_USING_SMP') == False:
     SrcRemove(src, ['cpu.c'])
 
-group = DefineGroup('Kernel', src, depend = [''], CPPPATH = CPPPATH)
+CPPDEFINES = ['__RTTHREAD__']
+
+group = DefineGroup('Kernel', src, depend = [''], CPPPATH = CPPPATH, CPPDEFINES = CPPDEFINES)
 
 Return('group')