diff --git a/frontend/mobile-app/lib/core/network/api_client.dart b/frontend/mobile-app/lib/core/network/api_client.dart
index 6eb1305d..c0554ade 100644
--- a/frontend/mobile-app/lib/core/network/api_client.dart
+++ b/frontend/mobile-app/lib/core/network/api_client.dart
@@ -384,7 +384,9 @@ class ApiClient {
       case DioExceptionType.badResponse:
         final statusCode = error.response?.statusCode;
         final data = error.response?.data;
+        debugPrint('[ApiClient] ▼▼▼ badResponse: status=$statusCode, data=$data, dataType=${data.runtimeType}');
         final rawMsg = data is Map ? data['message'] : null;
+        debugPrint('[ApiClient] ▼▼▼ rawMsg=$rawMsg, rawMsgType=${rawMsg.runtimeType}');
         final message = rawMsg is List
             ? (rawMsg as List).join(', ')
             : (rawMsg?.toString() ?? '请求失败');
diff --git a/frontend/mobile-app/lib/features/pre_planting/presentation/pages/pre_planting_purchase_page.dart b/frontend/mobile-app/lib/features/pre_planting/presentation/pages/pre_planting_purchase_page.dart
index d0eb3215..5295680a 100644
--- a/frontend/mobile-app/lib/features/pre_planting/presentation/pages/pre_planting_purchase_page.dart
+++ b/frontend/mobile-app/lib/features/pre_planting/presentation/pages/pre_planting_purchase_page.dart
@@ -348,12 +348,14 @@ class _PrePlantingPurchasePageState
       final prePlantingService = ref.read(prePlantingServiceProvider);
 
       // 创建预种订单（后端自动完成：扣款 → 分配权益 → 检查合并）
+      final pc = _isFirstPurchase ? _selectedProvinceCode : _position?.provinceCode;
+      final cc = _isFirstPurchase ? _selectedCityCode : _position?.cityCode;
+      debugPrint('[PrePlantingPurchase] ★ createOrder: qty=$_quantity, isFirst=$_isFirstPurchase, provinceCode=$pc, cityCode=$cc');
       final response = await prePlantingService.createOrder(
         portionCount: _quantity,
-        // 首次购买时传省市信息，续购时后端自动复用
-        provinceCode: _isFirstPurchase ? _selectedProvinceCode : _position?.provinceCode,
+        provinceCode: pc,
         provinceName: _isFirstPurchase ? _selectedProvinceName : _position?.provinceName,
-        cityCode: _isFirstPurchase ? _selectedCityCode : _position?.cityCode,
+        cityCode: cc,
         cityName: _isFirstPurchase ? _selectedCityName : _position?.cityName,
       );
 
@@ -376,8 +378,9 @@ class _PrePlantingPurchasePageState
         // 返回上一页（Profile 页面会自动刷新）
         context.pop(true);
       }
-    } catch (e) {
-      debugPrint('[PrePlantingPurchase] 购买失败: $e');
+    } catch (e, stack) {
+      debugPrint('[PrePlantingPurchase] ★ 购买失败 type=${e.runtimeType}: $e');
+      debugPrint('[PrePlantingPurchase] ★ stackTrace: $stack');
       if (mounted) {
         ScaffoldMessenger.of(context).showSnackBar(
           SnackBar(