diff --git a/inventory-backend/app/services/inbound/buy_service.py b/inventory-backend/app/services/inbound/buy_service.py
index 5fa056d..83bc411 100644
--- a/inventory-backend/app/services/inbound/buy_service.py
+++ b/inventory-backend/app/services/inbound/buy_service.py
@@ -117,7 +117,13 @@ class BuyInboundService:
 
             in_qty = float(data.get('in_quantity') or 0)
             u_price = float(data.get('unit_price') or 0)
-            tax_rate = float(data.get('tax_rate') or 0)  # [新增]
+            tax_rate = float(data.get('tax_rate') or 0)
+            
+            # 计算税后单价
+            post_tax_price = float(data.get('post_tax_unit_price') or 0)
+            if post_tax_price == 0 and u_price > 0:
+                tax_multiplier = 1 + (tax_rate / 100)
+                post_tax_price = u_price * tax_multiplier
 
             try:
                 seq_sql = text("SELECT nextval('global_print_seq')")
@@ -138,8 +144,8 @@ class BuyInboundService:
 
                 # 价格信息
                 pre_tax_unit_price=u_price,
-                post_tax_unit_price=float(data.get('post_tax_unit_price') or 0),
-                tax_rate=tax_rate,  # [新增]
+                post_tax_unit_price=post_tax_price,
+                tax_rate=tax_rate,
                 total_price=in_qty * u_price,
                 currency=data.get('currency', 'CNY'),
                 exchange_rate=data.get('exchange_rate', 1.0),
@@ -183,10 +189,22 @@ class BuyInboundService:
             if 'arrival_photo' in data: stock.arrival_photo = json.dumps(data['arrival_photo'])
             if 'inspection_report' in data: stock.inspection_report = json.dumps(data['inspection_report'])
 
-            # [新增] 更新税率
-            if 'tax_rate' in data: stock.tax_rate = float(data['tax_rate'])
+            # 更新税率
+            if 'tax_rate' in data: 
+                stock.tax_rate = float(data['tax_rate'])
+            
+            # 更新税前单价
+            if 'unit_price' in data: 
+                stock.pre_tax_unit_price = float(data['unit_price'])
+            
             # 更新税后单价
-            if 'post_tax_unit_price' in data: stock.post_tax_unit_price = float(data['post_tax_unit_price'])
+            if 'post_tax_unit_price' in data: 
+                stock.post_tax_unit_price = float(data['post_tax_unit_price'])
+            else:
+                # 如果税后单价没有提供，根据税前单价和税率计算
+                if 'unit_price' in data or 'tax_rate' in data:
+                    tax_multiplier = 1 + (float(data.get('tax_rate', stock.tax_rate or 0)) / 100)
+                    stock.post_tax_unit_price = float(stock.pre_tax_unit_price) * tax_multiplier
 
             if 'in_quantity' in data:
                 diff = float(data['in_quantity']) - float(stock.in_quantity)
@@ -195,8 +213,7 @@ class BuyInboundService:
                     stock.stock_quantity = float(stock.stock_quantity) + diff
                     stock.available_quantity = float(stock.available_quantity) + diff
 
-            if 'unit_price' in data: stock.pre_tax_unit_price = float(data['unit_price'])
-
+            # 重新计算总价
             stock.total_price = float(stock.in_quantity) * float(stock.pre_tax_unit_price)
             db.session.commit()
             return stock