diff --git a/adapter.go b/adapter.go
index dc7ee77..f7d85dc 100644
--- a/adapter.go
+++ b/adapter.go
@@ -327,6 +327,11 @@ func (a *Adapter) SavePolicy(model model.Model) error {
 		}
 	}
 
+	// check whether the policy is empty
+	if len(lines) == 0 {
+		return nil
+	}
+
 	_, err = a.engine.Insert(&lines)
 
 	return err