diff --git a/conf/app.ini b/conf/app.ini
index cf2ae31d83..6b3ce8d240 100644
--- a/conf/app.ini
+++ b/conf/app.ini
@@ -94,7 +94,7 @@ 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 =