diff --git a/YLErpDAL/Modules/ReportModule/SettlementMailTemplateHelper.cs b/YLErpDAL/Modules/ReportModule/SettlementMailTemplateHelper.cs
new file mode 100644
index 00000000..45edfdf4
--- /dev/null
+++ b/YLErpDAL/Modules/ReportModule/SettlementMailTemplateHelper.cs
@@ -0,0 +1,107 @@
+using System.Globalization;
+using Microsoft.EntityFrameworkCore;
+using YLErp.BLL;
+using YLErp.Modules.AppModule;
+
+namespace YLErp.Modules.ReportModule
+{
+    /// <summary>
+    /// 为结算确认书邮件准备交易编号和平仓总额模板变量。
+    /// </summary>
+    public static class SettlementMailTemplateHelper
+    {
+        /// <summary>
+        /// 根据当前客户的确认书反查对应交易和平仓记录。
+        /// 文档编号可能在不同文档类型中重复，因此必须同时匹配编号和类型。
+        /// </summary>
+        public static List<Datas> GetSettlementRows(YLContext dbContext, IEnumerable<trade_contract_document> documents, int clientId)
+        {
+            var documentKeys = documents
+                .Where(document => !string.IsNullOrWhiteSpace(document.Code))
+                .Select(document => BuildDocumentKey(document.Code, document.Type))
+                .Distinct()
+                .ToHashSet();
+
+            if (documentKeys.Count == 0)
+            {
+                return new List<Datas>();
+            }
+
+            var contractCodes = documents.Select(document => document.Code).Distinct().ToList();
+            var rows = (from relation in dbContext.trade_contract_r
+                        join tradeCash in dbContext.trade_cash on relation.TradeCashId equals tradeCash.id
+                        join tradeData in dbContext.trade on tradeCash.TradeId equals tradeData.id
+                        where contractCodes.Contains(relation.ContractCode)
+                              && relation.IsValid
+                              && !tradeCash.IsDeleted
+                              && tradeData.ClientId == clientId
+                        select new
+                        {
+                            relation.ContractCode,
+                            relation.Type,
+                            Trade = tradeData,
+                            TradeCash = tradeCash
+                        }).AsNoTracking().ToList();
+
+            return rows
+                // 数据库先按编号缩小范围，再在内存中用“编号+类型”精确匹配附件。
+                .Where(row => documentKeys.Contains(BuildDocumentKey(row.ContractCode, row.Type)))
+                .Select(row => new Datas
+                {
+                    trade = row.Trade,
+                    tradecash = row.TradeCash
+                }).ToList();
+        }
+
+        /// <summary>
+        /// 将批量加载的数据限制到当前结算日，避免跨日发送时变量汇总串日。
+        /// </summary>
+        public static List<Datas> ForValueDate(IEnumerable<Datas> rows, DateTime valueDate)
+        {
+            return (rows ?? Enumerable.Empty<Datas>())
+                .Where(row => row?.tradecash != null && row.tradecash.ValueDate.Date == valueDate.Date)
+                .ToList();
+        }
+
+        /// <summary>
+        /// 将去重后的交易编号及客户视角平仓总额写入邮件模板参数。
+        /// </summary>
+        public static void PopulateSettlementFields(MailInfoRequestModel request, IEnumerable<Datas> rows)
+        {
+            ArgumentNullException.ThrowIfNull(request);
+
+            // 同一平仓记录可能因关联多份文档重复出现，按 trade_cash.id 去重以避免重复计入金额。
+            var distinctRows = (rows ?? Enumerable.Empty<Datas>())
+                .Where(row => row?.trade != null && row.tradecash != null)
+                .GroupBy(row => row.tradecash.id)
+                .Select(group => group.First())
+                .ToList();
+
+            request.TradeNumber = string.Join(",", distinctRows
+                .Select(row => row.trade.TradeNumber)
+                .Where(number => !string.IsNullOrWhiteSpace(number))
+                .Distinct()
+                .OrderBy(number => number));
+
+            if (distinctRows.Count == 0)
+            {
+                request.UnwindTotalAmount = string.Empty;
+                return;
+            }
+
+            // trade_cash.Amount 为交易员视角，邮件展示需取反转换为客户视角。
+            var customerAmount = -distinctRows.Sum(row => row.tradecash.Amount);
+            if (customerAmount == 0)
+            {
+                // 消除浮点求和可能产生的 -0.00。
+                customerAmount = 0;
+            }
+            request.UnwindTotalAmount = customerAmount.ToString("F2", CultureInfo.InvariantCulture);
+        }
+
+        private static string BuildDocumentKey(string code, string type)
+        {
+            return $"{code}\u001f{type}";
+        }
+    }
+}