diff --git a/retry/option.go b/retry/option.go
index df810cd..bf00280 100644
--- a/retry/option.go
+++ b/retry/option.go
@@ -1,3 +1,17 @@
+// Copyright 2021 CloudWeGo Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package retry
 
 import "time"
diff --git a/retry/retry.go b/retry/retry.go
index 8f35aa6..9bff8d2 100644
--- a/retry/retry.go
+++ b/retry/retry.go
@@ -1,3 +1,17 @@
+// Copyright 2021 CloudWeGo Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package retry
 
 import "time"
diff --git a/retry/retry_test.go b/retry/retry_test.go
index 37d2ab6..f1ef156 100644
--- a/retry/retry_test.go
+++ b/retry/retry_test.go
@@ -1,3 +1,17 @@
+// Copyright 2021 CloudWeGo Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package retry
 
 import (