diff --git a/backend/src/main/java/com/qqchen/deploy/backend/deploy/repository/ISSHAuditLogRepository.java b/backend/src/main/java/com/qqchen/deploy/backend/deploy/repository/ISSHAuditLogRepository.java
index 2ea346fa..a8b15cc0 100644
--- a/backend/src/main/java/com/qqchen/deploy/backend/deploy/repository/ISSHAuditLogRepository.java
+++ b/backend/src/main/java/com/qqchen/deploy/backend/deploy/repository/ISSHAuditLogRepository.java
@@ -19,4 +19,9 @@ public interface ISSHAuditLogRepository extends IBaseRepository<SSHAuditLog, Lon
      * 统计用户当前活跃的SSH会话数
      */
     long countByUserIdAndDisconnectTimeIsNull(Long userId);
+    
+    /**
+     * 统计用户对指定服务器当前活跃的SSH会话数
+     */
+    long countByUserIdAndServerIdAndDisconnectTimeIsNull(Long userId, Long serverId);
 }
diff --git a/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/ISSHAuditLogService.java b/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/ISSHAuditLogService.java
index a1a12b54..44429109 100644
--- a/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/ISSHAuditLogService.java
+++ b/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/ISSHAuditLogService.java
@@ -47,4 +47,13 @@ public interface ISSHAuditLogService extends IBaseService<SSHAuditLog, SSHAuditL
      * @return 活跃会话数
      */
     long countUserActiveSessions(Long userId);
+    
+    /**
+     * 检查用户对指定服务器当前活跃的SSH会话数
+     *
+     * @param userId   用户ID
+     * @param serverId 服务器ID
+     * @return 活跃会话数
+     */
+    long countUserActiveSessionsForServer(Long userId, Long serverId);
 }
diff --git a/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/impl/SSHAuditLogServiceImpl.java b/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/impl/SSHAuditLogServiceImpl.java
index 63d41b15..833b5fd0 100644
--- a/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/impl/SSHAuditLogServiceImpl.java
+++ b/backend/src/main/java/com/qqchen/deploy/backend/deploy/service/impl/SSHAuditLogServiceImpl.java
@@ -22,6 +22,7 @@ import java.time.Duration;
 import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * SSH审计日志服务实现
@@ -37,47 +38,72 @@ public class SSHAuditLogServiceImpl
 
     @Resource
     private IUserService userService;
+    
+    /**
+     * 每个sessionId的锁对象，用于防止并发创建重复的审计日志
+     * Key: sessionId, Value: 锁对象
+     */
+    private final ConcurrentHashMap<String, Object> sessionLocks = new ConcurrentHashMap<>();
 
     public SSHAuditLogServiceImpl(ISSHAuditLogRepository auditLogRepository) {
         this.auditLogRepository = auditLogRepository;
     }
+    
+    /**
+     * 获取指定sessionId的锁对象（如果不存在则创建）
+     */
+    private Object getSessionLock(String sessionId) {
+        return sessionLocks.computeIfAbsent(sessionId, k -> new Object());
+    }
 
     @Override
     @Transactional(rollbackFor = Exception.class)
     public Long createAuditLog(Long userId, Server server, String sessionId, String clientIp, String userAgent) {
-        log.info("创建SSH审计日志: userId={}, serverId={}, sessionId={}", userId, server.getId(), sessionId);
+        // ⚠️ 关键：使用 sessionId 粒度的锁，确保同一个 sessionId 的创建操作串行执行
+        Object lock = getSessionLock(sessionId);
+        
+        synchronized (lock) {
+            log.info("创建SSH审计日志: userId={}, serverId={}, sessionId={}", userId, server.getId(), sessionId);
 
-        SSHAuditLog auditLog = new SSHAuditLog();
-        
-        // 用户信息
-        auditLog.setUserId(userId);
-        User user = userService.findEntityById(userId);
-        if (user != null) {
-            auditLog.setUsername(user.getUsername());
+            // ⚠️ 双重检查：在锁内再次检查是否已存在（防止并发重复创建）
+            SSHAuditLog existing = auditLogRepository.findBySessionId(sessionId);
+            if (existing != null) {
+                log.warn("SSH审计日志已存在，跳过创建: id={}, sessionId={}", existing.getId(), sessionId);
+                return existing.getId();
+            }
+
+            SSHAuditLog auditLog = new SSHAuditLog();
+            
+            // 用户信息
+            auditLog.setUserId(userId);
+            User user = userService.findEntityById(userId);
+            if (user != null) {
+                auditLog.setUsername(user.getUsername());
+            }
+            
+            // 服务器信息
+            auditLog.setServerId(server.getId());
+            auditLog.setServerName(server.getServerName());
+            auditLog.setServerIp(server.getHostIp());
+            
+            // 会话信息
+            auditLog.setSessionId(sessionId);
+            auditLog.setConnectTime(LocalDateTime.now());
+            
+            // 客户端信息
+            auditLog.setClientIp(clientIp);
+            auditLog.setUserAgent(userAgent);
+            
+            // 初始化
+            auditLog.setCommandCount(0);
+            auditLog.setCommands("[]");
+            auditLog.setStatus("CONNECTED");
+            
+            SSHAuditLog saved = auditLogRepository.save(auditLog);
+            log.info("SSH审计日志创建成功: id={}", saved.getId());
+            
+            return saved.getId();
         }
-        
-        // 服务器信息
-        auditLog.setServerId(server.getId());
-        auditLog.setServerName(server.getServerName());
-        auditLog.setServerIp(server.getHostIp());
-        
-        // 会话信息
-        auditLog.setSessionId(sessionId);
-        auditLog.setConnectTime(LocalDateTime.now());
-        
-        // 客户端信息
-        auditLog.setClientIp(clientIp);
-        auditLog.setUserAgent(userAgent);
-        
-        // 初始化
-        auditLog.setCommandCount(0);
-        auditLog.setCommands("[]");
-        auditLog.setStatus("CONNECTED");
-        
-        SSHAuditLog saved = auditLogRepository.save(auditLog);
-        log.info("SSH审计日志创建成功: id={}", saved.getId());
-        
-        return saved.getId();
     }
 
     @Override
@@ -136,6 +162,10 @@ public class SSHAuditLogServiceImpl
             log.info("SSH审计日志关闭: sessionId={}, status={}, duration={}秒", 
                      sessionId, status, auditLog.getDurationSeconds());
             
+            // ⚠️ 清理锁对象，避免内存泄漏
+            sessionLocks.remove(sessionId);
+            log.debug("清理sessionId锁对象: sessionId={}", sessionId);
+            
         } catch (Exception e) {
             log.error("关闭审计日志失败: sessionId={}", sessionId, e);
         }
@@ -146,6 +176,11 @@ public class SSHAuditLogServiceImpl
         return auditLogRepository.countByUserIdAndDisconnectTimeIsNull(userId);
     }
 
+    @Override
+    public long countUserActiveSessionsForServer(Long userId, Long serverId) {
+        return auditLogRepository.countByUserIdAndServerIdAndDisconnectTimeIsNull(userId, serverId);
+    }
+
     /**
      * 解析命令JSON
      */