diff --git a/src/YhCore.Service/Impl/LogService.cs b/src/YhCore.Service/Impl/LogService.cs
new file mode 100644
index 0000000..7583afd
--- /dev/null
+++ b/src/YhCore.Service/Impl/LogService.cs
@@ -0,0 +1,53 @@
+using System.Threading.Tasks;
+using YhCore.Entity;
+using YhCore.Model.Vo;
+using YhCore.Repository;
+using YhCore.Service.Interfaces;
+
+namespace YhCore.Service.Impl
+{
+    /// <summary>
+    /// 日志查询服务（对应 Java 版 LogServiceImpl，替换框架期 LogServiceStub）。
+    /// 查询 sys_operation_log：按学校隔离；systemScope=false 排除查询类（GET=LogLevel 3）；
+    /// keyword 模糊匹配用户名/URI/类方法/请求参数/异常/操作类型；按 CreateTime 倒序分页。
+    /// </summary>
+    public class LogService : ILogService
+    {
+        /// <summary>查询类日志级别（与 SysOperationLogFilter 推导一致：GET → 3/QUERY）</summary>
+        private const int QueryLogLevel = 3;
+
+        /// <summary>每页大小上限（审计日志量大，防一次拉全表）</summary>
+        private const int MaxPageSize = 200;
+
+        private readonly IRepository<SysOperationLog> _log;
+
+        public LogService(IRepository<SysOperationLog> log)
+        {
+            _log = log;
+        }
+
+        public Task<PageVO<SysOperationLog>> SearchAsync(int schId, string keyword, bool systemScope, int page, int size)
+        {
+            if (page < 0) page = 0;
+            if (size <= 0) size = 20;
+            if (size > MaxPageSize) size = MaxPageSize;
+
+            var kw = keyword?.Trim();
+
+            return _log.PageAsync(
+                a => a.SchId == schId
+                     // 普通操作日志：只看增删改（排除查询类）；系统操作日志全量
+                     && (systemScope || a.LogLevel != QueryLogLevel)
+                     // 关键字模糊匹配（EF 翻译为 SQL LIKE，NULL 列不命中）
+                     && (string.IsNullOrEmpty(kw)
+                         || a.UserName.Contains(kw)
+                         || a.RequestUri.Contains(kw)
+                         || a.ClassMethod.Contains(kw)
+                         || a.RequestParams.Contains(kw)
+                         || a.ErrorMsg.Contains(kw)
+                         || a.OperationType.Contains(kw)),
+                page, size,
+                a => a.CreateTime, asc: false);
+        }
+    }
+}