diff --git a/src/main/java/com/gunshi/project/xyt/service/ReservoirWaterService.java b/src/main/java/com/gunshi/project/xyt/service/ReservoirWaterService.java
index 1ac6666..4a035db 100644
--- a/src/main/java/com/gunshi/project/xyt/service/ReservoirWaterService.java
+++ b/src/main/java/com/gunshi/project/xyt/service/ReservoirWaterService.java
@@ -182,12 +182,11 @@ public class ReservoirWaterService {
         //最新水位时间往前推24小时水位
         LocalDateTime now = LocalDateTime.ofInstant(tm.toInstant(), ZoneId.systemDefault());
         LocalDateTime dateTime = now.minusDays(1);
-        BigDecimal oldRz = attResBaseMapper.oldRz(stcd,1,Date.from(dateTime.atZone(ZoneId.systemDefault()).toInstant()));
+        BigDecimal oldRz = attResBaseMapper.oldRz(stcd,2,Date.from(dateTime.atZone(ZoneId.systemDefault()).toInstant()));
 
-        if(oldRz == null){
-            return vo;
+        if(oldRz != null){
+            vo.setRzDiff(rz.subtract(oldRz));
         }
-        vo.setRzDiff(rz.subtract(oldRz));
 
         //本年最高水位
         BigDecimal maxYearRz = queryYearRzByStcdAndTime(stcd);