diff --git a/oss_tool/aliyun_oss.go b/oss_tool/aliyun_oss.go
index 6c489e7..5fc8a66 100644
--- a/oss_tool/aliyun_oss.go
+++ b/oss_tool/aliyun_oss.go
@@ -40,9 +40,8 @@ func (c *ALiYunOSSClient) GetSignUrl(bucket string, key string, expires time.Dur
 	result, err = c.ossClient.Presign(
 		context.Background(),
 		&oss.PutObjectRequest{
-			Bucket:      oss.Ptr(bucket),
-			Key:         oss.Ptr(key),
-			ContentType: oss.Ptr("application/octet-stream"),
+			Bucket: oss.Ptr(bucket),
+			Key:    oss.Ptr(key),
 		},
 		oss.PresignExpires(expires),
 	)