diff --git a/mhd_bms/src/main/java/com/mhd/bms/domain/billingStatement/service/BillingStatementDomainService.java b/mhd_bms/src/main/java/com/mhd/bms/domain/billingStatement/service/BillingStatementDomainService.java
index b18d7bc8a..34be902e5 100644
--- a/mhd_bms/src/main/java/com/mhd/bms/domain/billingStatement/service/BillingStatementDomainService.java
+++ b/mhd_bms/src/main/java/com/mhd/bms/domain/billingStatement/service/BillingStatementDomainService.java
@@ -538,8 +538,9 @@ public class BillingStatementDomainService {
             currentMonthPaymentDate = DateUtil.offsetDay(currentMonthPaymentDate, paymentDay - 1);
             // 结束时间：本月出账日的前一天
             Date cycleEndTime = DateUtil.offsetDay(currentMonthPaymentDate, -1);
-            // 开始时间：上个月的出账日
-            Date cycleBeginTime = DateUtil.offsetMonth(currentMonthPaymentDate, -1);
+            // 开始时间：上个月的出账日（明确计算上个月的第一天，然后加上出账日-1天）
+            Date lastMonthFirstDay = DateUtil.beginOfMonth(DateUtil.offsetMonth(businessDate, -1));
+            Date cycleBeginTime = DateUtil.offsetDay(lastMonthFirstDay, paymentDay - 1);
             
             billingStatementDO.setCycleBeginTime(cycleBeginTime);
             billingStatementDO.setCycleEndTime(cycleEndTime);