diff --git a/weed/shell/command_volume_balance.go b/weed/shell/command_volume_balance.go
index d7ef0d005..faece77d2 100644
--- a/weed/shell/command_volume_balance.go
+++ b/weed/shell/command_volume_balance.go
@@ -27,7 +27,7 @@ func (c *commandVolumeBalance) Name() string {
 func (c *commandVolumeBalance) Help() string {
 	return `balance all volumes among volume servers
 
-	volume.balance [-c ALL|EACH_COLLECTION|<collection_name>] [-force] [-dataCenter=<data_center_name>]
+	volume.balance [-collection ALL|EACH_COLLECTION|<collection_name>] [-force] [-dataCenter=<data_center_name>]
 
 	Algorithm: