diff --git a/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/mapper/BuildMapper.xml b/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/mapper/BuildMapper.xml
index 9c383ec3..0e96cd61 100644
--- a/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/mapper/BuildMapper.xml
+++ b/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/mapper/BuildMapper.xml
@@ -36,11 +36,11 @@
                 AND DEL_FLAG = #{jxlb.delFlag}
             </if>
         </where>
-        ORDER BY 序号
+        ORDER BY CASE WHEN REGEXP_LIKE(序号, '^[0-9]+$') THEN CAST(序号 AS INT) END NULLS LAST, 序号
     </select>
 
     <select id="selectMaxXh" resultType="java.lang.String">
-        SELECT MAX(序号) FROM 教学楼表 WHERE DEL_FLAG = 0
+        SELECT MAX(CAST(序号 AS INT)) FROM 教学楼表 WHERE DEL_FLAG = 0 AND REGEXP_LIKE(序号, '^[0-9]+$')
     </select>
 
 </mapper>
diff --git a/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/service/impl/BuildServiceImpl.java b/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/service/impl/BuildServiceImpl.java
index 0abd2a34..8b799db6 100644
--- a/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/service/impl/BuildServiceImpl.java
+++ b/backend/roomroot-jwgl/src/main/java/com/roomroot/jwgl/service/impl/BuildServiceImpl.java
@@ -173,7 +173,8 @@ public class BuildServiceImpl implements BuildService {
         }
         // 只返回未删除的教学楼（与 pageList 口径一致，避免已删除数据出现在下拉/全量列表里）
         wrapper.eq(JXLB::getDelFlag, 0);
-        wrapper.orderByAsc(JXLB::getXh);
+        // 序号为字符串列，按自然数排序（非数字排在最后按字典序），与 pageList 口径一致
+        wrapper.last("ORDER BY CASE WHEN REGEXP_LIKE(序号, '^[0-9]+$') THEN CAST(序号 AS INT) END NULLS LAST, 序号");
         return buildMapper.selectList(wrapper);
     }