diff --git a/ruoyi-admin/src/main/java/com/ruoyi/web/controller/tyre/BizMaintenanceOrderController.java b/ruoyi-admin/src/main/java/com/ruoyi/web/controller/tyre/BizMaintenanceOrderController.java
index ea6a662e..0e0975c7 100644
--- a/ruoyi-admin/src/main/java/com/ruoyi/web/controller/tyre/BizMaintenanceOrderController.java
+++ b/ruoyi-admin/src/main/java/com/ruoyi/web/controller/tyre/BizMaintenanceOrderController.java
@@ -2,12 +2,14 @@ package com.ruoyi.web.controller.tyre;
 
 import com.alibaba.fastjson.JSONObject;
 import com.ruoyi.common.annotation.Log;
+import com.ruoyi.common.annotation.RepeatSubmit;
 import com.ruoyi.common.config.RuoYiConfig;
 import com.ruoyi.common.core.controller.BaseController;
 import com.ruoyi.common.core.domain.AjaxResult;
 import com.ruoyi.common.core.page.TableDataInfo;
 import com.ruoyi.common.enums.BusinessType;
 import com.ruoyi.common.utils.DateUtils;
+import com.ruoyi.common.utils.StringUtils;
 import com.ruoyi.common.utils.file.FileUploadUtils;
 import com.ruoyi.common.utils.poi.ExcelUtil;
 import com.ruoyi.system.domain.*;
@@ -22,6 +24,7 @@ import org.springframework.web.multipart.MultipartFile;
 
 import java.io.IOException;
 import java.math.BigDecimal;
+import java.time.LocalDate;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -188,7 +191,21 @@ public class BizMaintenanceOrderController extends BaseController {
      */
     @PostMapping("/PDAAddMaintenanceOrder")
     @ResponseBody
-    public AjaxResult PDAAddMaintenanceOrder(@RequestBody BizMaintenanceOrder bizMaintenanceOrder) {
+    @RepeatSubmit
+    @Transactional(rollbackFor = Exception.class)
+    public synchronized AjaxResult PDAAddMaintenanceOrder(@RequestBody BizMaintenanceOrder bizMaintenanceOrder) {
+        if (bizMaintenanceOrder == null) {
+            return error("参数不能为空");
+        }
+        if (StringUtils.isEmpty(bizMaintenanceOrder.getPlateNumber())) {
+            return error("车牌号不能为空");
+        }
+        if (StringUtils.isEmpty(bizMaintenanceOrder.getTypeCode())) {
+            return error("维保类型不能为空");
+        }
+        if (bizMaintenanceOrderService.countSameDayMaintenanceOrder(bizMaintenanceOrder) > 0) {
+            return error("同一车辆同一维保类型当天只能生成一次工单");
+        }
         String orderNo = orderNoCreate();
         bizMaintenanceOrder.setOrderNo(orderNo);
         return toAjax(bizMaintenanceOrderService.insertBizMaintenanceOrder(bizMaintenanceOrder));
@@ -290,10 +307,12 @@ public class BizMaintenanceOrderController extends BaseController {
 
     private String orderNoCreate() {
         // 查询当天的工单号（返回的是当天最新的一条记录）
-        BizMaintenanceOrder bizMaintenanceOrder = bizMaintenanceOrderService.selectBizMaintenanceOrderTD();
+        BizMaintenanceOrder query = new BizMaintenanceOrder();
+        fillTodayRange(query);
+        BizMaintenanceOrder bizMaintenanceOrder = bizMaintenanceOrderService.selectBizMaintenanceOrderTD(query);
 
         String orderNo;
-        String today = new java.text.SimpleDateFormat("yyyyMMdd").format(new java.util.Date());
+        String today = DateUtils.dateTime();
 
         if (bizMaintenanceOrder == null) {
             // 当天没有工单，从001开始
@@ -312,4 +331,11 @@ public class BizMaintenanceOrderController extends BaseController {
         }
         return orderNo;
     }
+
+    private void fillTodayRange(BizMaintenanceOrder bizMaintenanceOrder) {
+        LocalDate today = LocalDate.now();
+        // 使用 Java 计算当天半开区间，避免在 Mapper 中写 MySQL/SQL Server 不兼容的日期函数。
+        bizMaintenanceOrder.getParams().put("beginTime", DateUtils.toDate(today));
+        bizMaintenanceOrder.getParams().put("endTime", DateUtils.toDate(today.plusDays(1)));
+    }
 }
diff --git a/ruoyi-system/src/main/java/com/ruoyi/system/mapper/BizMaintenanceOrderMapper.java b/ruoyi-system/src/main/java/com/ruoyi/system/mapper/BizMaintenanceOrderMapper.java
index c55921e0..8d6891d2 100644
--- a/ruoyi-system/src/main/java/com/ruoyi/system/mapper/BizMaintenanceOrderMapper.java
+++ b/ruoyi-system/src/main/java/com/ruoyi/system/mapper/BizMaintenanceOrderMapper.java
@@ -62,7 +62,9 @@ public interface BizMaintenanceOrderMapper
      */
     public int deleteBizMaintenanceOrderByOrderIds(String[] orderIds);
 
-    BizMaintenanceOrder selectBizMaintenanceOrderTD();
+    BizMaintenanceOrder selectBizMaintenanceOrderTD(BizMaintenanceOrder bizMaintenanceOrder);
 
     BizMaintenanceOrder selectBizMaintenanceOrderByOrderIdBefore(BizMaintenanceOrder bizMaintenanceOrder);
+
+    int countSameDayMaintenanceOrder(BizMaintenanceOrder bizMaintenanceOrder);
 }
diff --git a/ruoyi-system/src/main/java/com/ruoyi/system/service/IBizMaintenanceOrderService.java b/ruoyi-system/src/main/java/com/ruoyi/system/service/IBizMaintenanceOrderService.java
index 952cc018..b59bf32d 100644
--- a/ruoyi-system/src/main/java/com/ruoyi/system/service/IBizMaintenanceOrderService.java
+++ b/ruoyi-system/src/main/java/com/ruoyi/system/service/IBizMaintenanceOrderService.java
@@ -63,7 +63,9 @@ public interface IBizMaintenanceOrderService
     List<BizMaintenanceOrder> selectBizMaintenanceOrderListTwo(BizMaintenanceOrder bizMaintenanceOrder);
 
 
-    BizMaintenanceOrder selectBizMaintenanceOrderTD();
+    BizMaintenanceOrder selectBizMaintenanceOrderTD(BizMaintenanceOrder bizMaintenanceOrder);
 
     BizMaintenanceOrder selectBizMaintenanceOrderByOrderIdBefore(BizMaintenanceOrder bizMaintenanceOrder);
+
+    int countSameDayMaintenanceOrder(BizMaintenanceOrder bizMaintenanceOrder);
 }
diff --git a/ruoyi-system/src/main/java/com/ruoyi/system/service/impl/BizMaintenanceOrderServiceImpl.java b/ruoyi-system/src/main/java/com/ruoyi/system/service/impl/BizMaintenanceOrderServiceImpl.java
index 22cb056b..9560c784 100644
--- a/ruoyi-system/src/main/java/com/ruoyi/system/service/impl/BizMaintenanceOrderServiceImpl.java
+++ b/ruoyi-system/src/main/java/com/ruoyi/system/service/impl/BizMaintenanceOrderServiceImpl.java
@@ -1,10 +1,10 @@
 package com.ruoyi.system.service.impl;
 
+import java.time.LocalDate;
 import java.util.List;
 
 import com.ruoyi.common.annotation.DataScope;
 import com.ruoyi.common.utils.DateUtils;
-import com.ruoyi.common.utils.ShiroUtils;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 import com.ruoyi.system.mapper.BizMaintenanceOrderMapper;
@@ -112,12 +112,21 @@ public class BizMaintenanceOrderServiceImpl implements IBizMaintenanceOrderServi
     }
 
     @Override
-    public BizMaintenanceOrder selectBizMaintenanceOrderTD() {
-        return bizMaintenanceOrderMapper.selectBizMaintenanceOrderTD();
+    public BizMaintenanceOrder selectBizMaintenanceOrderTD(BizMaintenanceOrder bizMaintenanceOrder) {
+        return bizMaintenanceOrderMapper.selectBizMaintenanceOrderTD(bizMaintenanceOrder);
     }
 
     @Override
     public BizMaintenanceOrder selectBizMaintenanceOrderByOrderIdBefore(BizMaintenanceOrder bizMaintenanceOrder) {
         return bizMaintenanceOrderMapper.selectBizMaintenanceOrderByOrderIdBefore(bizMaintenanceOrder);
     }
+
+    @Override
+    public int countSameDayMaintenanceOrder(BizMaintenanceOrder bizMaintenanceOrder) {
+        LocalDate today = LocalDate.now();
+        // PDA 新增工单按“生成当天”限次，日期边界由 Java 生成，Mapper 只做范围比较以兼容 MySQL/SQL Server。
+        bizMaintenanceOrder.getParams().put("beginTime", DateUtils.toDate(today));
+        bizMaintenanceOrder.getParams().put("endTime", DateUtils.toDate(today.plusDays(1)));
+        return bizMaintenanceOrderMapper.countSameDayMaintenanceOrder(bizMaintenanceOrder);
+    }
 }
diff --git a/ruoyi-system/src/main/resources/mapper/tyre/BizMaintenanceOrderMapper.xml b/ruoyi-system/src/main/resources/mapper/tyre/BizMaintenanceOrderMapper.xml
index 02782331..94bfd23d 100644
--- a/ruoyi-system/src/main/resources/mapper/tyre/BizMaintenanceOrderMapper.xml
+++ b/ruoyi-system/src/main/resources/mapper/tyre/BizMaintenanceOrderMapper.xml
@@ -114,13 +114,25 @@ PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 
         where order_id = #{orderId}
     </select>
-    <select id="selectBizMaintenanceOrderTD" resultMap="BizMaintenanceOrderResult">
+    <select id="selectBizMaintenanceOrderTD" parameterType="BizMaintenanceOrder" resultMap="BizMaintenanceOrderResult">
         SELECT
             MAX(order_no) as order_no
         FROM
             biz_maintenance_order
         WHERE
-            DATE(create_time) = CURDATE();
+            create_time &gt;= #{params.beginTime}
+            AND create_time &lt; #{params.endTime}
+    </select>
+    <select id="countSameDayMaintenanceOrder" parameterType="BizMaintenanceOrder" resultType="int">
+        SELECT
+            COUNT(1)
+        FROM
+            biz_maintenance_order
+        WHERE
+            plate_number = #{plateNumber}
+            AND type_code = #{typeCode}
+            AND create_time &gt;= #{params.beginTime}
+            AND create_time &lt; #{params.endTime}
     </select>
     <select id="selectBizMaintenanceOrderByOrderIdBefore"
             resultMap="BizMaintenanceOrderResult" parameterType="BizMaintenanceOrder">