diff --git a/src/onebot/helper/data.ts b/src/onebot/helper/data.ts
index 34a5cf45..29409c4d 100644
--- a/src/onebot/helper/data.ts
+++ b/src/onebot/helper/data.ts
@@ -90,6 +90,7 @@ export class OB11Construct {
             file_name: file.fileName,
             busid: file.busId,
             size: +file.fileSize,
+            file_size: +file.fileSize,
             upload_time: file.uploadTime,
             dead_time: file.deadTime,
             modify_time: file.modifyTime,
diff --git a/src/onebot/types/data.ts b/src/onebot/types/data.ts
index 8b3acab2..5a6a972e 100644
--- a/src/onebot/types/data.ts
+++ b/src/onebot/types/data.ts
@@ -75,6 +75,7 @@ export interface OB11Sender {
 }
 
 export interface OB11GroupFile {
+    file_size: number; // 文件大小 GOCQHTTP 群文件Api扩展
     group_id: number; // 群ID
     file_id: string; // 文件ID
     file_name: string; // 文件名称