diff --git a/YD_YiLu/Services/Impl/DeviceSyncService.cs b/YD_YiLu/Services/Impl/DeviceSyncService.cs
index b1c2647..687cddf 100644
--- a/YD_YiLu/Services/Impl/DeviceSyncService.cs
+++ b/YD_YiLu/Services/Impl/DeviceSyncService.cs
@@ -161,19 +161,41 @@ namespace YD_YiLu.Api.Services.Impl
                 return result;
 
             // 👉 2. 批量查已存在的 TrainSerial（防重复）
-            var trainSerials = list.Select(x => x.TrainSerial).ToList();
+            var normalizedItems = list
+                .Where(x => x != null
+                    && !string.IsNullOrWhiteSpace(x.DeviceSerial)
+                    && !string.IsNullOrWhiteSpace(x.UserSerial))
+                .Select(x =>
+                {
+                    var trainSerial = NormalizeTrainSerial(x.TrainSerial, x);
+                    var videoSerial = NormalizeSerial(x.VideoSerial, trainSerial);
+                    return new
+                    {
+                        Item = x,
+                        TrainSerial = trainSerial,
+                        VideoSerial = videoSerial
+                    };
+                })
+                .ToList();
+
+            if (!normalizedItems.Any())
+                return result;
+
+            var trainSerials = normalizedItems.Select(x => x.TrainSerial).Distinct().ToList();
 
             var existSerials = await _context.YL_Train
                 .Where(x => trainSerials.Contains(x.TrainSerial))
                 .Select(x => x.TrainSerial)
                 .ToListAsync();
+            var seenSerials = new HashSet<string>(existSerials, StringComparer.OrdinalIgnoreCase);
 
             var newEntities = new List<YL_Train>();
 
-            foreach (var item in list)
+            foreach (var normalized in normalizedItems)
             {
+                var item = normalized.Item;
                 // 👉 3. 唯一校验（跳过已存在）
-                if (existSerials.Contains(item.TrainSerial))
+                if (!seenSerials.Add(normalized.TrainSerial))
                     continue;
 
                 var entity = new YL_Train
@@ -182,8 +204,8 @@ namespace YD_YiLu.Api.Services.Impl
                     DeviceType = item.DeviceType,
                     UserSerial = item.UserSerial,
 
-                    TrainSerial = item.TrainSerial,
-                    VideoSerial = item.VideoSerial,
+                    TrainSerial = normalized.TrainSerial,
+                    VideoSerial = normalized.VideoSerial,
 
                     TrainExam = item.TrainExam,
                     QuizId = item.QuizId,
@@ -876,6 +898,38 @@ namespace YD_YiLu.Api.Services.Impl
             return dto;
         }
 
+        private static string NormalizeTrainSerial(string serial, DeviceSyncTrainPushRequestDto item)
+        {
+            if (!string.IsNullOrWhiteSpace(serial))
+                return NormalizeSerial(serial, "AUTO-" + MD5Helper.MD5Encrypt32(serial));
+
+            var seed = string.Join("|", new[]
+            {
+                item.DeviceSerial,
+                item.UserSerial,
+                item.CourseId.ToString(),
+                item.TrainExam.ToString(),
+                item.StartTime,
+                item.EndTime,
+                item.Duration.ToString(),
+                item.StandardCounts.ToString(),
+                item.UnStandardCounts.ToString(),
+                item.Distance?.ToString() ?? "",
+                item.TimeKeeping?.ToString() ?? ""
+            });
+
+            return "AUTO-" + MD5Helper.MD5Encrypt32(seed);
+        }
+
+        private static string NormalizeSerial(string serial, string fallback)
+        {
+            var value = string.IsNullOrWhiteSpace(serial) ? fallback : serial.Trim();
+            if (value.Length <= 64)
+                return value;
+
+            return "AUTO-" + MD5Helper.MD5Encrypt32(value);
+        }
+
         private static (DateTime? start, DateTime? end) GetDateRange(int dateType, string queryStart, string queryEnd)
         {
             var now = DateTime.Now;