diff --git a/xCAT-server/lib/xcat/plugins/aixinstall.pm b/xCAT-server/lib/xcat/plugins/aixinstall.pm
index 6610e429a..1382a8860 100644
--- a/xCAT-server/lib/xcat/plugins/aixinstall.pm
+++ b/xCAT-server/lib/xcat/plugins/aixinstall.pm
@@ -8782,7 +8782,7 @@ sub chkosimage_usage
 	push @{$rsp->{data}}, "  Usage: ";
 	push @{$rsp->{data}}, "\tchkosimage [-h | --help]";
 	push @{$rsp->{data}}, "or";
-	push @{$rsp->{data}}, "\tchkosimage [-V] image_name\n";
+	push @{$rsp->{data}}, "\tchkosimage [-V] [-c|--clean] image_name\n";
 	xCAT::MsgUtils->message("I", $rsp, $callback);
 	return 0;
 }