diff --git a/lib/report_generator.py b/lib/report_generator.py
index 33a4a14..6aef469 100644
--- a/lib/report_generator.py
+++ b/lib/report_generator.py
@@ -268,7 +268,10 @@ def generate_excel(orders, selected_fields, sum_fields, sum_results,
             for cell in row:
                 if cell.value:
                     max_length = max(max_length, len(str(cell.value)))
-        ws.column_dimensions[ws.cell(row=1, column=col_idx).column_letter].width = min(max_length + 2, 50)
+        # 使用 openpyxl 的列字母转换函数
+        from openpyxl.utils import get_column_letter
+        col_letter = get_column_letter(col_idx)
+        ws.column_dimensions[col_letter].width = min(max_length + 2, 50)
     
     # 保存文件
     wb.save(file_path)