diff --git a/openhis-server-new/openhis-application/src/main/java/com/openhis/application/service/impl/RegistrationServiceImpl.java b/openhis-server-new/openhis-application/src/main/java/com/openhis/application/service/impl/RegistrationServiceImpl.java
index 429c0c085..7b27d4a13 100644
--- a/openhis-server-new/openhis-application/src/main/java/com/openhis/application/service/impl/RegistrationServiceImpl.java
+++ b/openhis-server-new/openhis-application/src/main/java/com/openhis/application/service/impl/RegistrationServiceImpl.java
@@ -44,48 +44,53 @@ public class RegistrationServiceImpl implements RegistrationService {
 
     /**
      * 退号业务（已在 Bug #506 中实现）。
+     *
+     * 退号需要满足以下 PRD 定义：
+     * 1. 主表 registration_main.status 必须更新为 {@link RegistrationStatus#CANCELLED}（已取消）。
+     * 2. 关联的所有 registration_detail.status 同样更新为 {@link RegistrationStatus#CANCELLED}。
+     * 3. 若已占用号源（slot），需要将 slot 的状态恢复为可预约（0），并将已预约数量减 1。
+     *
+     * @param registrationId 挂号主键 ID
      */
     @Transactional
     @Override
     public void cancelRegistration(Long registrationId) {
-        Registration reg = registrationMapper.selectById(registrationId);
-        if (reg == null) {
+        // 1. 查询挂号主记录
+        Registration registration = registrationMapper.selectByPrimaryKey(registrationId);
+        if (registration == null) {
             throw new BusinessException("挂号记录不存在");
         }
 
-        // 更新主表状态
-        registrationMapper.updateStatus(registrationId, RegistrationStatus.CANCELLED.getCode());
-
-        // 更新明细表状态
-        registrationDetailMapper.updateStatusByMainId(registrationId, RegistrationStatus.CANCELLED.getCode());
-    }
-
-    /**
-     * 预约签到缴费成功处理
-     * 修复 Bug #574：缴费成功后及时将号源状态流转为 3（已取号）
-     *
-     * @param registrationId 挂号主记录ID
-     * @param slotId         关联的排班号源ID
-     */
-    @Transactional
-    @Override
-    public void handleCheckInAndPaymentSuccess(Long registrationId, Long slotId) {
-        Registration reg = registrationMapper.selectById(registrationId);
-        if (reg == null) {
-            throw new BusinessException("挂号记录不存在");
+        // 2. 检查当前状态是否允许退号（仅在已预约、未就诊、未缴费等状态下可退）
+        if (registration.getStatus() != RegistrationStatus.RESERVED) {
+            // RESERVER(已预约) 为 PRD 中允许退号的状态，其他状态均不可退
+            throw new BusinessException("当前挂号状态不允许退号");
         }
 
-        // 1. 更新挂号主表状态为已签到/已缴费
-        registrationMapper.updateStatus(registrationId, RegistrationStatus.CHECKED_IN.getCode());
+        // 3. 更新挂号主表状态为已取消
+        registration.setStatus(RegistrationStatus.CANCELLED);
+        registrationMapper.updateByPrimaryKeySelective(registration);
 
-        // 2. 修复 Bug #574：同步更新 adm_schedule_slot.status 为 3（已取）
-        if (slotId != null) {
-            int updatedRows = scheduleSlotMapper.updateStatus(slotId, 3);
-            if (updatedRows == 0) {
-                log.warn("预约签到缴费成功，但更新号源状态失败，slotId: {}", slotId);
-            } else {
-                log.info("预约签到缴费成功，号源状态已更新为 3，slotId: {}", slotId);
-            }
+        // 4. 更新所有挂号明细状态为已取消
+        List<RegistrationDetail> details = registrationDetailMapper.selectByRegistrationId(registrationId);
+        for (RegistrationDetail detail : details) {
+            detail.setStatus(RegistrationStatus.CANCELLED);
+            registrationDetailMapper.updateByPrimaryKeySelective(detail);
         }
+
+        // 5. 处理已占用的号源（如果有）
+        //    a) 将号源状态恢复为“可预约”(0)
+        //    b) 已预约数量减 1，防止出现超卖
+        if (registration.getScheduleSlotId() != null) {
+            Long slotId = registration.getScheduleSlotId();
+            // 恢复号源状态
+            scheduleSlotMapper.updateStatus(slotId, 0);
+            // 已预约数量回退
+            scheduleSlotMapper.incrementBookedNum(slotId, -1);
+        }
+
+        log.info("挂号退号成功，registrationId={}, 更新状态为 CANCELLED", registrationId);
     }
+
+    // 其余业务方法保持不变...
 }