diff --git a/conf/app.ini b/conf/app.ini
index 30d6c7d483..ec5fcb23b3 100644
--- a/conf/app.ini
+++ b/conf/app.ini
@@ -91,7 +91,7 @@ ENABLE_SET_COOKIE = true
 GC_INTERVAL_TIME = 86400
 ; Session life time, default is 86400
 SESSION_LIFE_TIME = 86400
-; Session id hash func, default is sha1
+; session id hash func, Either "sha1", "sha256" or "md5" default is sha1
 SESSION_ID_HASHFUNC = sha1
 ; Session hash key, default is use random string
 SESSION_ID_HASHKEY =