diff --git a/yy-admin-master/YY.Admin.Services/Service/Print/NativePrintRenderService.cs b/yy-admin-master/YY.Admin.Services/Service/Print/NativePrintRenderService.cs
index 62dc0af..00ec733 100644
--- a/yy-admin-master/YY.Admin.Services/Service/Print/NativePrintRenderService.cs
+++ b/yy-admin-master/YY.Admin.Services/Service/Print/NativePrintRenderService.cs
@@ -1017,14 +1017,18 @@ public static class NativePrintRenderService
         var colList = columns.OfType<JsonObject>().ToList();
         if (mergeColumnKeys.Length > 0)
         {
-            var byKey = colList.ToDictionary(
-                c => ReadAsString(c["key"]) ?? string.Empty,
-                c => ReadAsString(c["bindField"]) ?? ReadAsString(c["field"]) ?? string.Empty);
+            // 用 GroupBy 兜底，避免重复 key 抛异常；按 mergeColumnKeys 给定顺序输出对应 bindField/field
+            var byKey = colList
+                .GroupBy(c => ReadAsString(c["key"]) ?? string.Empty)
+                .ToDictionary(
+                    g => g.Key,
+                    g => ReadAsString(g.First()["bindField"]) ?? ReadAsString(g.First()["field"]) ?? string.Empty);
             return mergeColumnKeys
                 .Select(k => byKey.TryGetValue(k, out var f) ? f : string.Empty)
                 .Where(f => !string.IsNullOrEmpty(f))
                 .ToList();
         }
+        // 兼容老的列级 mergeByValue 开关
         return colList
             .Where(c => string.Equals(ReadAsString(c["mergeByValue"]), "true", StringComparison.OrdinalIgnoreCase))
             .Select(c => ReadAsString(c["bindField"]) ?? ReadAsString(c["field"]) ?? string.Empty)
diff --git a/yy-admin-master/YY.Admin/Views/Print/PrintPreviewWindow.xaml.cs b/yy-admin-master/YY.Admin/Views/Print/PrintPreviewWindow.xaml.cs
index f26a1e7..93983c1 100644
--- a/yy-admin-master/YY.Admin/Views/Print/PrintPreviewWindow.xaml.cs
+++ b/yy-admin-master/YY.Admin/Views/Print/PrintPreviewWindow.xaml.cs
@@ -109,6 +109,8 @@ public partial class PrintPreviewWindow : HandyControl.Controls.Window
 
     /// <summary>
     /// 根据模板绑定字段生成参数 JSON（便于用户直接编辑并预览）。
+    /// 与 web 端 nativeMockData.ts 保持一致：识别 mergeColumnKeys 让同组相邻行字段值相同，
+    /// 以便在预览中触发 rowSpan 合并显示。
     /// </summary>
     private static string BuildMockParamJson(string templateJson)
     {
@@ -121,6 +123,7 @@ public partial class PrintPreviewWindow : HandyControl.Controls.Window
             var obj = new JsonObject();
             var elements = root?["elements"]?.AsArray() ?? new JsonArray();
             var fields = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            var rng = new Random();
 
             foreach (var el in elements.OfType<JsonObject>())
             {
@@ -130,28 +133,73 @@ public partial class PrintPreviewWindow : HandyControl.Controls.Window
                     var source = (el["source"]?.ToString() ?? "mainTable").Trim();
                     if (!obj.ContainsKey(source))
                     {
-                        var rows = new JsonArray();
                         var columns = el["columns"]?.AsArray() ?? new JsonArray();
-                        for (var i = 1; i <= 8; i++)
+                        var colList = columns.OfType<JsonObject>().ToList();
+
+                        // 解析合并字段顺序：根据 mergeColumnKeys 按 column.key 映射到 bindField
+                        var mergeKeys = (el["mergeColumnKeys"]?.AsArray() ?? new JsonArray())
+                            .Select(n => n?.ToString() ?? string.Empty)
+                            .Where(s => !string.IsNullOrEmpty(s))
+                            .ToList();
+                        var strictGrouping = !string.Equals(
+                            el["strictGrouping"]?.ToString() ?? "true", "false",
+                            StringComparison.OrdinalIgnoreCase);
+
+                        var mergeFieldOrder = mergeKeys
+                            .Select(k => colList.FirstOrDefault(c => string.Equals(c["key"]?.ToString() ?? string.Empty, k, StringComparison.Ordinal)))
+                            .Where(c => c != null)
+                            .Select(c => (c!["bindField"]?.ToString() ?? c!["field"]?.ToString() ?? string.Empty).Trim())
+                            .Where(s => !string.IsNullOrEmpty(s))
+                            .ToList();
+
+                        var rows = new JsonArray();
+                        JsonObject? prevRow = null;
+                        for (var i = 0; i < 8; i++)
                         {
                             var row = new JsonObject();
-                            foreach (var col in columns.OfType<JsonObject>())
+                            foreach (var col in colList)
                             {
                                 var field = (col["bindField"]?.ToString() ?? col["field"]?.ToString() ?? string.Empty).Trim();
                                 if (string.IsNullOrWhiteSpace(field)) continue;
                                 var contentType = (col["contentType"]?.ToString() ?? "text").Trim().ToLowerInvariant();
+                                fields.Add(field);
+
+                                var mergeIndex = mergeFieldOrder.IndexOf(field);
+                                var enableMerge = mergeIndex >= 0;
+
+                                if (enableMerge)
+                                {
+                                    // 父级合并字段在 strictGrouping 下必须与前一行一致，才允许沿用前一行值
+                                    var canFollowPrev = !strictGrouping || mergeIndex == 0 || (prevRow != null &&
+                                        mergeFieldOrder.Take(mergeIndex).All(parent =>
+                                            (prevRow[parent]?.ToString() ?? string.Empty) == (row[parent]?.ToString() ?? string.Empty)));
+
+                                    if (i > 0 && prevRow != null && canFollowPrev && rng.NextDouble() < 0.5)
+                                    {
+                                        // 沿用前一行此字段值，从而触发合并
+                                        var prevVal = prevRow[field];
+                                        row[field] = prevVal != null ? JsonNode.Parse(prevVal.ToJsonString()) : (JsonNode?)$"{field}_合并组1";
+                                    }
+                                    else
+                                    {
+                                        // 新合并组：随机 0-3 表示组编号
+                                        row[field] = $"{field}_合并组{rng.Next(1, 5)}";
+                                    }
+                                    continue;
+                                }
+
                                 row[field] = contentType switch
                                 {
-                                    "number" => i * 123.45,
-                                    "amount" => i * 24567.89,
-                                    "qrcode" => $"QR_{field}_{i}",
-                                    "barcode" => $"BAR_{field}_{i}",
-                                    "image" => $"https://picsum.photos/seed/{Uri.EscapeDataString(field + "_" + i)}/260/120",
-                                    _ => $"{field}_示例值_{i}"
+                                    "number" => (i + 1) * 123.45,
+                                    "amount" => (i + 1) * 24567.89,
+                                    "qrcode" => $"QR_{field}_{i + 1}",
+                                    "barcode" => $"BAR_{field}_{i + 1}",
+                                    "image" => $"https://picsum.photos/seed/{Uri.EscapeDataString(field + "_" + (i + 1))}/260/120",
+                                    _ => $"{field}_示例值_{i + 1}"
                                 };
-                                fields.Add(field);
                             }
                             rows.Add(row);
+                            prevRow = row;
                         }
                         obj[source] = rows;
                     }