diff --git a/im-center-server/src/main/java/cn/axzo/im/group/LegacyGroupSupport.java b/im-center-server/src/main/java/cn/axzo/im/group/LegacyGroupSupport.java
index 6dfc7d6..02f5fbc 100644
--- a/im-center-server/src/main/java/cn/axzo/im/group/LegacyGroupSupport.java
+++ b/im-center-server/src/main/java/cn/axzo/im/group/LegacyGroupSupport.java
@@ -4,6 +4,7 @@ import cn.axzo.im.dao.mapper.ChatGroupMapper;
 import cn.axzo.im.dao.repository.GroupDao;
 import cn.axzo.im.entity.ChatGroup;
 import cn.axzo.im.entity.Group;
+import com.google.common.collect.Sets;
 import lombok.RequiredArgsConstructor;
 import org.apache.commons.collections4.CollectionUtils;
 import org.apache.commons.lang3.math.NumberUtils;
@@ -27,7 +28,13 @@ public class LegacyGroupSupport {
     private final GroupDao groupDao;
     private final ChatGroupMapper chatGroupMapper;
 
-    public List<String> getGroupAccounts(Set<String> groupIds) {
+    public Set<String> getMergedAccounts(Set<String> groupIds) {
+        Set<String> accounts = Sets.newHashSet(getGroupAccounts(groupIds));
+        accounts.addAll(getGroupCatAccounts(groupIds));
+        return accounts;
+    }
+
+    private List<String> getGroupAccounts(Set<String> groupIds) {
         if (CollectionUtils.isEmpty(groupIds))
             return Collections.emptyList();
         if (parseLongs(groupIds).isEmpty())
@@ -40,7 +47,7 @@ public class LegacyGroupSupport {
                 .collect(toList());
     }
 
-    public List<String> getGroupCatAccounts(Set<String> groupIds) {
+    private List<String> getGroupCatAccounts(Set<String> groupIds) {
         if (CollectionUtils.isEmpty(groupIds))
             return Collections.emptyList();
         return chatGroupMapper.selectList(
diff --git a/im-center-server/src/main/java/cn/axzo/im/service/impl/MessageTaskServiceImpl.java b/im-center-server/src/main/java/cn/axzo/im/service/impl/MessageTaskServiceImpl.java
index 44a1bbe..f4d1843 100644
--- a/im-center-server/src/main/java/cn/axzo/im/service/impl/MessageTaskServiceImpl.java
+++ b/im-center-server/src/main/java/cn/axzo/im/service/impl/MessageTaskServiceImpl.java
@@ -48,7 +48,6 @@ import org.springframework.util.CollectionUtils;
 import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -413,10 +412,7 @@ public class MessageTaskServiceImpl extends ServiceImpl<MessageTaskMapper, Messa
                 .map(MessageTask.ReceivePerson::getImAccount)
                 .filter(StringUtils::isNotBlank)
                 .collect(toSet());
-        HashSet<String> result = new HashSet<>();
-        result.addAll(legacyGroupSupport.getGroupAccounts(imAccounts));
-        result.addAll(legacyGroupSupport.getGroupCatAccounts(imAccounts));
-        return result;
+        return legacyGroupSupport.getMergedAccounts(imAccounts);
     }
 
     private String resolveBody(MessageTask.ReceivePerson receivePerson,