diff --git a/backend/mci-server/src/main/java/com/sino/mci/channel/dto/BindConversationAccountRequest.java b/backend/mci-server/src/main/java/com/sino/mci/channel/dto/BindConversationAccountRequest.java
index 53cf4a8..deffcb7 100644
--- a/backend/mci-server/src/main/java/com/sino/mci/channel/dto/BindConversationAccountRequest.java
+++ b/backend/mci-server/src/main/java/com/sino/mci/channel/dto/BindConversationAccountRequest.java
@@ -2,6 +2,7 @@ package com.sino.mci.channel.dto;
 
 import jakarta.validation.constraints.NotNull;
 import lombok.Data;
+import org.hibernate.validator.constraints.Range;
 
 @Data
 public class BindConversationAccountRequest {
@@ -10,6 +11,7 @@ public class BindConversationAccountRequest {
     private Long accountId;
 
     @NotNull
+    @Range(min = 1, max = 4)
     private Integer bindingType;
 
     private Integer sortOrder;
diff --git a/backend/mci-server/src/main/java/com/sino/mci/channel/service/ConversationService.java b/backend/mci-server/src/main/java/com/sino/mci/channel/service/ConversationService.java
index 4bcedeb..f79cb9a 100644
--- a/backend/mci-server/src/main/java/com/sino/mci/channel/service/ConversationService.java
+++ b/backend/mci-server/src/main/java/com/sino/mci/channel/service/ConversationService.java
@@ -104,14 +104,11 @@ public class ConversationService {
     public void bindAccount(String tenantCode, Long conversationId, BindConversationAccountRequest request) {
         getConversation(tenantCode, conversationId);
 
-        ChannelAccountConversation existing = bindingMapper.selectOne(
+        bindingMapper.delete(
                 new LambdaQueryWrapper<ChannelAccountConversation>()
                         .eq(ChannelAccountConversation::getAccountId, request.getAccountId())
                         .eq(ChannelAccountConversation::getConversationId, conversationId)
                         .eq(ChannelAccountConversation::getBindingType, request.getBindingType()));
-        if (existing != null) {
-            throw new BusinessException("该账号已绑定此会话的相同类型");
-        }
 
         ChannelAccountConversation binding = new ChannelAccountConversation();
         binding.setAccountId(request.getAccountId());
diff --git a/backend/mci-server/src/main/java/com/sino/mci/send/service/SendService.java b/backend/mci-server/src/main/java/com/sino/mci/send/service/SendService.java
index 4d345b0..3195d0d 100644
--- a/backend/mci-server/src/main/java/com/sino/mci/send/service/SendService.java
+++ b/backend/mci-server/src/main/java/com/sino/mci/send/service/SendService.java
@@ -9,7 +9,9 @@ import com.sino.mci.channel.common.dto.SendMessageResult;
 import com.sino.mci.channel.common.model.ChannelType;
 import com.sino.mci.channel.common.spi.ChannelAdapter;
 import com.sino.mci.channel.entity.ChannelAccount;
+import com.sino.mci.channel.entity.ChannelAccountConversation;
 import com.sino.mci.channel.entity.Conversation;
+import com.sino.mci.channel.repository.ChannelAccountConversationMapper;
 import com.sino.mci.channel.repository.ChannelAccountMapper;
 import com.sino.mci.channel.repository.ConversationMapper;
 import com.sino.mci.channel.service.AccountSelector;
@@ -80,6 +82,7 @@ public class SendService {
     private final SendRecordMapper sendRecordMapper;
     private final ConversationMapper conversationMapper;
     private final ChannelAccountMapper accountMapper;
+    private final ChannelAccountConversationMapper channelAccountConversationMapper;
     private final ChannelIdentityMapper channelIdentityMapper;
     private final PersonMapper personMapper;
     private final TagMapper tagMapper;
@@ -332,6 +335,12 @@ public class SendService {
         if (accountId == null) {
             throw new BusinessException("会话未配置发送账号: " + conversationId);
         }
+        ChannelAccount account = accountMapper.selectById(accountId);
+        if (account == null || !tenantCode.equals(account.getTenantCode())
+                || !channelType.name().equalsIgnoreCase(account.getChannelType())
+                || account.getStatus() == null || account.getStatus() != STATUS_ENABLED) {
+            throw new BusinessException("会话没有可用的发送账号: " + conversationId);
+        }
         SendTarget target = new SendTarget();
         target.setConversationId(conversationId);
         target.setPersonId(null);
@@ -356,6 +365,14 @@ public class SendService {
         if (accountId == null) {
             throw new BusinessException("租户未配置可用发送账号: channel=" + channelType.name().toLowerCase());
         }
+        ChannelAccount account = accountMapper.selectById(accountId);
+        if (account == null || !tenantCode.equals(account.getTenantCode())
+                || account.getStatus() == null || account.getStatus() != STATUS_ENABLED) {
+            throw new BusinessException("租户没有可用的发送账号: channel=" + channelType.name().toLowerCase());
+        }
+        if (!channelType.name().equalsIgnoreCase(account.getChannelType())) {
+            throw new BusinessException("单聊发送账号渠道类型与目标身份不一致");
+        }
         SendTarget target = new SendTarget();
         target.setConversationId(null);
         target.setPersonId(personId);
@@ -675,7 +692,24 @@ public class SendService {
     }
 
     private Long selectSendAccount(String tenantCode, Long conversationId, ChannelType channelType, Map<String, Object> channelStrategy) {
-        return accountSelector.selectSendAccount(tenantCode, conversationId, channelType, extractStrategy(channelStrategy));
+        List<Integer> bindingTypes = List.of(1, 2);
+        for (Integer bindingType : bindingTypes) {
+            List<ChannelAccountConversation> bindings = channelAccountConversationMapper.selectList(
+                    new LambdaQueryWrapper<ChannelAccountConversation>()
+                            .eq(ChannelAccountConversation::getConversationId, conversationId)
+                            .eq(ChannelAccountConversation::getBindingType, bindingType)
+                            .eq(ChannelAccountConversation::getStatus, STATUS_ENABLED)
+                            .orderByAsc(ChannelAccountConversation::getSortOrder));
+            for (ChannelAccountConversation binding : bindings) {
+                ChannelAccount account = accountMapper.selectById(binding.getAccountId());
+                if (account != null && tenantCode.equals(account.getTenantCode())
+                        && channelType.name().equalsIgnoreCase(account.getChannelType())
+                        && account.getStatus() != null && account.getStatus() == STATUS_ENABLED) {
+                    return account.getId();
+                }
+            }
+        }
+        return null;
     }
 
     private Long selectDefaultAccount(String tenantCode, ChannelType channelType) {