diff --git a/emis-biz/src/main/java/com/xdadan/erp/emis/service/EmisBaseService.java b/emis-biz/src/main/java/com/xdadan/erp/emis/service/EmisBaseService.java
index 9fddaf1bd..86d8479a7 100644
--- a/emis-biz/src/main/java/com/xdadan/erp/emis/service/EmisBaseService.java
+++ b/emis-biz/src/main/java/com/xdadan/erp/emis/service/EmisBaseService.java
@@ -33,6 +33,7 @@ package com.xdadan.erp.emis.service;
  import com.xdadan.erp.system.service.ISysConfigService;
  import com.xdadan.erp.system.service.ISysNoticeService;
  import com.xdadan.erp.system.service.ISysUserService;
+ import jodd.util.StringUtil;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.commons.collections.MapUtils;
  import org.apache.commons.lang3.StringUtils;
@@ -46,6 +47,9 @@ package com.xdadan.erp.emis.service;
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.time.Instant;
+ import java.time.LocalDate;
+ import java.time.ZoneId;
+ import java.time.format.DateTimeParseException;
  import java.time.temporal.ChronoUnit;
  import java.util.*;
  import java.util.stream.Collectors;
@@ -4050,6 +4054,40 @@ public class EmisBaseService {
          return copy;
      }
 
+     /**
+      * 检查月结客户首次签约日期，首次签约之前开的不允许修改
+      *
+      * @param emisWaybillOld
+      * @throws EmisBizError
+      */
+     protected void checkFirstSigningDay(EmisWaybill emisWaybillOld) throws EmisBizError {
+         if (emisWaybillOld == null || emisWaybillOld.getOrderDate() == null || StringUtil.isBlank(emisWaybillOld.getCustNo())) {
+             return;
+         }
+
+         EmisCustomerUser emisCustomerUser = emisCustomerUserMapper
+                 .selectMonthCustomerByMonthlyPayCode(emisWaybillOld.getCustNo());
+         if (emisCustomerUser == null || StringUtil.isBlank(emisCustomerUser.getFirstSigningDay())) {
+             return;
+         }
+
+         try {
+             LocalDate firstSigningDate = LocalDate.parse(emisCustomerUser.getFirstSigningDay());
+             LocalDate orderDate = emisWaybillOld.getOrderDate().toInstant()
+                     .atZone(ZoneId.systemDefault())
+                     .toLocalDate();
+
+             if (orderDate.isBefore(firstSigningDate)) {
+                 throw new EmisBizError(EmisBizErrorType.PARAM_ERROR,
+                         String.format("运单日期(%s)不能早于客户首次签约日期(%s)",
+                                 orderDate, firstSigningDate));
+             }
+         } catch (DateTimeParseException e) {
+             log.error("客户首次签约日期格式错误: {}", emisCustomerUser.getFirstSigningDay(), e);
+             throw new EmisBizError(EmisBizErrorType.PARAM_ERROR, "客户首次签约日期格式错误");
+         }
+     }
+
      public static void main(String[] args) throws ParseException {
 //         Date startDate = new Date("202");
          Date startDate= new SimpleDateFormat("yyyy-MM-dd").parse("2025-05-11");