diff --git a/registry/registry.go b/registry/registry.go
index e9210604bbcced22f7e4493717f7ce6e96675590..2225d2c1fc6d465bfbf27cd9622d7296e4596d8f 100644
--- a/registry/registry.go
+++ b/registry/registry.go
@@ -68,7 +68,10 @@ type Registry interface {
 
 // nolint
 type NotifyListener interface {
-	// Notify supports notifications on the service interface and the dimension of the data type.
+	// Notify supports notifications on the service interface and the dimension of the data type. When a list of
+	// events are passed in, it's considered as a complete list, on the other side, if one single event is
+	// passed in, then it's a incremental event. Pls. note when a list (instead of single event) comes,
+	// the impl of NotifyListener may abandon the accumulated result from previous notifications.
 	Notify(...*ServiceEvent)
 }