diff --git a/coolq/api.go b/coolq/api.go
index 960830f..2fa0bee 100644
--- a/coolq/api.go
+++ b/coolq/api.go
@@ -124,7 +124,13 @@ func (bot *CQBot) CQSendGroupMessage(groupId int64, i interface{}) MSG {
 	// fix at display
 	for _, e := range elem {
 		if at, ok := e.(*message.AtElement); ok && at.Target != 0 {
-			at.Display = "@" + bot.Client.FindGroup(groupId).FindMember(at.Target).DisplayName()
+			at.Display = "@" + func() string {
+				mem := bot.Client.FindGroup(groupId).FindMember(at.Target)
+				if mem != nil {
+					return mem.DisplayName()
+				}
+				return strconv.FormatInt(at.Target, 10)
+			}()
 		}
 	}
 	mid := bot.SendGroupMessage(groupId, &message.SendingMessage{Elements: elem})
diff --git a/coolq/bot.go b/coolq/bot.go
index ba27714..c095bf7 100644
--- a/coolq/bot.go
+++ b/coolq/bot.go
@@ -95,7 +95,7 @@ func (bot *CQBot) SendGroupMessage(groupId int64, m *message.SendingMessage) int
 	var newElem []message.IMessageElement
 	for _, elem := range m.Elements {
 		if i, ok := elem.(*message.ImageElement); ok {
-			_, _ = bot.Client.UploadGroupImage(int64(rand.Intn(11451419198)), i.Data)
+			_, _ = bot.Client.UploadGroupImage(int64(rand.Intn(11451419)), i.Data)
 			gm, err := bot.Client.UploadGroupImage(groupId, i.Data)
 			if err != nil {
 				log.Warnf("警告: 群 %v 消息图片上传失败: %v", groupId, err)