diff --git a/cmd/sealer/cmd/image/build.go b/cmd/sealer/cmd/image/build.go
index b00a3e0f8e7..c78e233ed39 100644
--- a/cmd/sealer/cmd/image/build.go
+++ b/cmd/sealer/cmd/image/build.go
@@ -446,6 +446,7 @@ func saveDockerfileAsTempfile(dockerFileContent string) (string, error) {
 	if err != nil {
 		return "", err
 	}
+	defer f.Close()
 
 	defer func() {
 		if err != nil {