diff --git a/global.go b/global.go
index 1daf034..a2198ad 100644
--- a/global.go
+++ b/global.go
@@ -148,3 +148,6 @@ var videoType = "mp4"
 // ZombieText 检测僵尸好友字符串
 // 发送该字符给好友，能正常发送不报错的为正常好友，否则为僵尸好友
 const ZombieText = "وُحfخe ̷̴̐nخg ̷̴̐cخh ̷̴̐aخo امارتيخ ̷̴̐خ\n"
+
+// FileHelper 文件传输助手
+const FileHelper = "filehelper"
diff --git a/message.go b/message.go
index afaeb16..5a23ea5 100644
--- a/message.go
+++ b/message.go
@@ -114,9 +114,10 @@ func (m *Message) Receiver() (*User, error) {
 		return m.bot.self.User, nil
 	}
 	// https://github.com/eatmoreapple/openwechat/issues/113
-	if m.ToUserName == m.bot.self.fileHelper.UserName {
-		return m.bot.self.fileHelper.User, nil
+	if m.ToUserName == FileHelper {
+		return m.bot.self.FileHelper().User, nil
 	}
+
 	if m.IsSendByGroup() {
 		groups, err := m.bot.self.Groups()
 		if err != nil {
diff --git a/user.go b/user.go
index c69211c..81b6fe5 100644
--- a/user.go
+++ b/user.go
@@ -789,7 +789,7 @@ func newFriend(username string, self *Self) *Friend {
 // NewFriendHelper 创建一个文件传输助手
 // 文件传输助手的微信身份标识符永远是filehelper
 func NewFriendHelper(self *Self) *Friend {
-	return newFriend("filehelper", self)
+	return newFriend(FileHelper, self)
 }
 
 // SendTextToMp 发送文本消息给公众号