diff --git a/pjcloud-canteen/pjcloud-canteen-biz/src/main/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImpl.java b/pjcloud-canteen/pjcloud-canteen-biz/src/main/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImpl.java
index e10bb2ede..6e166fc78 100644
--- a/pjcloud-canteen/pjcloud-canteen-biz/src/main/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImpl.java
+++ b/pjcloud-canteen/pjcloud-canteen-biz/src/main/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImpl.java
@@ -164,14 +164,15 @@ public class CanteenSpuServiceImpl extends ServiceImpl<CanteenSpuMapper, Canteen
                 return R.failed(MsgUtils.getMessage(ErrorCodes.HARD_PRODUCT_STOCK_LOW,
                         StrUtil.blankToDefault(spu.getName(), "商品")));
             }
-            if (applyOperation) {
-                // 不得把“库存恰好等于目标值”当成本业务已经执行；该值可能由另一个业务号并发扣减得到。
-                // 幂等成功只能依赖上方读取到的 APPLIED 状态，状态缺失时必须从调用方快照原子更新。
+            if (applyOperation && item.getIncrCount() < 0) {
+                // 负增量扣减必须以快照做前置校验：不得把“库存恰好等于目标值”当成本业务已经执行，
+                // 该值可能由另一个业务号并发扣减得到，且并发扣减基于同一剩余量判断会超卖。
+                // 正增量恢复是可交换操作，不做快照校验，见下方更新循环注释。
                 if (spu.getStock() != expectedStock) {
                     return R.failed(MsgUtils.getMessage(ErrorCodes.CANTEEN_STOCK_CHANGED,
                             StrUtil.blankToDefault(spu.getName(), "商品")));
                 }
-            } else if ("APPLIED".equals(state)) {
+            } else if (rollbackOperation && "APPLIED".equals(state)) {
                 int rollbackDelta = -item.getIncrCount();
                 if (rollbackDelta < 0 && spu.getStock() < Math.abs(rollbackDelta)) {
                     return R.failed(MsgUtils.getMessage(ErrorCodes.HARD_PRODUCT_STOCK_LOW,
@@ -192,8 +193,17 @@ public class CanteenSpuServiceImpl extends ServiceImpl<CanteenSpuMapper, Canteen
                 continue;
             }
             // 状态缺失的 ROLLBACK 说明没有可确认的成功 APPLY，只写入终态阻断延迟请求，不能按库存值猜测并恢复。
-            if (applyOperation && baseMapper.updateStockIfMatch(item.getId(), delta, expectedStock) == 0) {
-                throw new I18nBizException(ErrorCodes.CANTEEN_STOCK_CHANGED, "");
+            if (applyOperation) {
+                // 正增量恢复库存是可交换操作：并发下单或退款改变的库存不影响本业务恢复量的正确性，
+                // 直接原子累加即可，幂等仍由 bizId 分布式锁和 Redis 状态保证，
+                // 避免退款恢复被其他业务号的并发库存变更误判为冲突（“库存已变化”）。
+                // 负增量扣减保留快照 CAS 条件更新，防止不同业务号基于同一剩余量重复判断导致超卖。
+                int updated = delta > 0 ? baseMapper.updateStock(item.getId(), delta)
+                        : baseMapper.updateStockIfMatch(item.getId(), delta, expectedStock);
+                if (updated == 0) {
+                    throw new I18nBizException(delta > 0 ? ErrorCodes.CANTEEN_STOCK_UPDATE_FAIL
+                            : ErrorCodes.CANTEEN_STOCK_CHANGED, "");
+                }
             }
         }
         String targetState = applyOperation ? "APPLIED"
@@ -277,7 +287,9 @@ public class CanteenSpuServiceImpl extends ServiceImpl<CanteenSpuMapper, Canteen
 				return R.failed(MsgUtils.getMessage(ErrorCodes.HARD_PRODUCT_STOCK_LOW,
 						StrUtil.blankToDefault(spu == null ? null : spu.getName(), "商品")));
 			}
-			if (applyOperation && current != expectedStock) {
+			// 正增量恢复是可交换操作，跳过剩余量快照校验，避免退款恢复被并发下单等无关变更误拒；
+			// 负增量扣减保留快照校验，防止不同业务号基于同一剩余量重复判断导致超卖。
+			if (applyOperation && item.getIncrCount() < 0 && current != expectedStock) {
 				CanteenSpuEntity spu = baseMapper.selectById(item.getId());
 				return R.failed(MsgUtils.getMessage(ErrorCodes.CANTEEN_STOCK_CHANGED,
 						StrUtil.blankToDefault(spu == null ? null : spu.getName(), "商品")));
@@ -306,13 +318,18 @@ public class CanteenSpuServiceImpl extends ServiceImpl<CanteenSpuMapper, Canteen
 				continue;
 			}
 			if (applyOperation) {
+				// 正增量恢复直接原子累加：expected 传 null 跳过剩余量匹配条件（SQL 仍保留不退成负销量、
+				// 不超配额的边界保护），并发变更不影响恢复正确性，幂等由 bizId 锁和 Redis 状态保证；
+				// 负增量扣减保留快照匹配条件更新，防止不同业务号基于同一剩余量重复判断导致超卖。
+				Integer expected = delta > 0 ? null : item.getBeforeStock();
 				updated = offline
 						? canteenDailyMenuMapper.updateOfflineStockDelta(dto.getMerchantId(), item.getMealDate(),
-								item.getHourType(), item.getId(), delta, item.getBeforeStock())
+								item.getHourType(), item.getId(), delta, expected)
 						: canteenDailyMenuMapper.updateOnlineStockDelta(dto.getMerchantId(), item.getMealDate(),
-								item.getHourType(), item.getId(), delta, item.getBeforeStock());
+								item.getHourType(), item.getId(), delta, expected);
 				if (updated == 0) {
-					throw new I18nBizException(ErrorCodes.CANTEEN_STOCK_CHANGED, "");
+					throw new I18nBizException(delta > 0 ? ErrorCodes.CANTEEN_STOCK_UPDATE_FAIL
+							: ErrorCodes.CANTEEN_STOCK_CHANGED, "");
 				}
 			}
 		}
diff --git a/pjcloud-canteen/pjcloud-canteen-biz/src/test/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImplTest.java b/pjcloud-canteen/pjcloud-canteen-biz/src/test/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImplTest.java
index efc9b963d..6ce609ed2 100644
--- a/pjcloud-canteen/pjcloud-canteen-biz/src/test/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImplTest.java
+++ b/pjcloud-canteen/pjcloud-canteen-biz/src/test/java/com/bsd/pjcloud/canteen/service/impl/CanteenSpuServiceImplTest.java
@@ -5,9 +5,13 @@ import com.bsd.pjcloud.canteen.entity.CanteenSpuEntity;
 import com.bsd.pjcloud.canteen.mapper.CanteenSpuMapper;
 import com.bsd.pjcloud.canteen.service.CanteenSpuService;
 import com.bsd.pjcloud.canteen.util.CanteenMerchantScopeHelper;
+import com.bsd.pjcloud.common.core.util.R;
+import com.bsd.pjcloud.common.core.util.SpringContextHolder;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.context.MessageSource;
 import org.springframework.data.redis.core.StringRedisTemplate;
 import org.springframework.data.redis.core.ValueOperations;
 import org.springframework.test.util.ReflectionTestUtils;
@@ -15,9 +19,16 @@ import org.springframework.transaction.support.TransactionSynchronizationManager
 
 import java.time.Duration;
 import java.util.List;
+import java.util.Locale;
 
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
@@ -55,10 +66,13 @@ class CanteenSpuServiceImplTest {
     @AfterEach
     void tearDown() {
         TransactionSynchronizationManager.clearSynchronization();
+        // 撤销最小 MessageSource 注入，避免静态 SpringContextHolder 影响后续测试类。
+        ReflectionTestUtils.setField(SpringContextHolder.class, "beanFactory", null);
     }
 
     /**
      * 已确认应用后完成补偿的售后库存允许再次 APPLY；否则钱包成功后的任务重试会丢失库存恢复。
+     * 正增量恢复走无条件原子累加，不再与快照做 CAS 对比。
      */
     @Test
     void compensatedRefundInventoryShouldAllowRetry() {
@@ -66,15 +80,48 @@ class CanteenSpuServiceImplTest {
         when(valueOperations.get("canteen:spu:order-stock:HARD_DAILY_MENU_AFTER_SALE:9"))
                 .thenReturn("COMPENSATED");
         when(spuMapper.selectById(1L)).thenReturn(spu(10));
-        when(spuMapper.updateStockIfMatch(1L, 2, 10)).thenReturn(1);
+        when(spuMapper.updateStock(1L, 2)).thenReturn(1);
 
         assertTrue(service.updateSkuStockIdempotent(dto).isOk());
 
-        verify(spuMapper).updateStockIfMatch(1L, 2, 10);
+        verify(spuMapper).updateStock(1L, 2);
         verify(valueOperations).set("canteen:spu:order-stock:HARD_DAILY_MENU_AFTER_SALE:9", "APPLIED",
                 Duration.ofDays(7));
     }
 
+    /**
+     * 正增量恢复是可交换操作：快照与当前库存不一致（并发下单/退款已改变库存）时仍应直接累加成功，
+     * 不得被误判为“库存已变化”阻断退款。
+     */
+    @Test
+    void restoreApplyShouldIgnoreConcurrentStockChange() {
+        CanteenSpuUpdateStockReqDTO dto = stockRequest("APPLY", 2, 10);
+        when(spuMapper.selectById(1L)).thenReturn(spu(8));
+        when(spuMapper.updateStock(1L, 2)).thenReturn(1);
+
+        assertTrue(service.updateSkuStockIdempotent(dto).isOk());
+
+        verify(spuMapper).updateStock(1L, 2);
+        verify(valueOperations).set("canteen:spu:order-stock:HARD_DAILY_MENU_AFTER_SALE:9", "APPLIED",
+                Duration.ofDays(7));
+    }
+
+    /**
+     * 负增量扣减仍要求当前库存等于快照，防止不同业务号基于同一剩余量重复判断导致超卖。
+     */
+    @Test
+    void deductApplyShouldStillRejectChangedStock() {
+        registerMinimalMessageSource();
+        CanteenSpuUpdateStockReqDTO dto = stockRequest("APPLY", -2, 10);
+        when(spuMapper.selectById(1L)).thenReturn(spu(8));
+
+        R result = service.updateSkuStockIdempotent(dto);
+
+        assertFalse(result.isOk());
+        verify(spuMapper, never()).updateStock(anyLong(), anyInt());
+        verify(spuMapper, never()).updateStockIfMatch(anyLong(), anyInt(), anyInt());
+    }
+
     /**
      * 已执行 APPLY 的回滚必须标记为可重试补偿态，区别于阻断网络延迟 APPLY 的未确认回滚态。
      */
@@ -93,6 +140,19 @@ class CanteenSpuServiceImplTest {
                 Duration.ofDays(7));
     }
 
+    /**
+     * 为纯 Mockito 环境注入最小 MessageSource，使 R.failed 分支的 MsgUtils 文案解析可用；
+     * 文案内容不影响断言，直接回显错误码。
+     */
+    private void registerMinimalMessageSource() {
+        MessageSource messageSource = mock(MessageSource.class);
+        when(messageSource.getMessage(anyString(), any(), any(Locale.class)))
+                .thenAnswer(invocation -> invocation.getArgument(0, String.class));
+        ConfigurableListableBeanFactory factory = mock(ConfigurableListableBeanFactory.class);
+        when(factory.getBean("pjcloudMessageSource")).thenReturn(messageSource);
+        new SpringContextHolder().postProcessBeanFactory(factory);
+    }
+
     /**
      * 构造单个基础 SPU 的幂等库存请求。
      *