diff --git a/app/cross_compare_report.py b/app/cross_compare_report.py
index 73cc0f0..371c5ca 100644
--- a/app/cross_compare_report.py
+++ b/app/cross_compare_report.py
@@ -45,11 +45,9 @@ def gen_cross_compare_report(params):
     date_list = check_param(params, 'date_list') # 优化后
     if not date_list or len(date_list) < 1:
         return json.dumps(make_common_res(7, '缺少日期参数，请最少选择一天作为查询日期'))
-    date_list = list(map(str, date_list))
     compare_date_list = check_param(params, 'compare_date_list') # 优化前
     if not compare_date_list or len(compare_date_list) < 1:
         return json.dumps(make_common_res(6, '缺少对比日期参数，请最少选择一天作为对比日期'))
-    compare_date_list = list(map(str, compare_date_list))
     query_type = check_param(params, 'query_type')
     if not query_type:
         query_type = 0
@@ -618,11 +616,12 @@ def cancel_collect_report(params):
 
 
 def transition_date_list4screen(date_list):
-    for i in range(0, len(date_list)):
-        if len(date_list[i]) == 1:
-            date_list[i] = [datetime.datetime.strptime(date_list[i][0], '%Y%m%d').strftime('%Y-%m-%d'), datetime.datetime.strptime(date_list[i][0], '%Y%m%d').strftime('%Y-%m-%d')]
-        elif len(date_list[i]) == 2:
-            date_list[i] = [datetime.datetime.strptime(date_list[i][0], '%Y%m%d').strftime('%Y-%m-%d'), datetime.datetime.strptime(date_list[i][1], '%Y%m%d').strftime('%Y-%m-%d')]
-        elif len(date_list[i]) > 2:
-            date_list[i] = [datetime.datetime.strptime(date_list[i][0], '%Y%m%d').strftime('%Y-%m-%d'), datetime.datetime.strptime(date_list[i][-1], '%Y%m%d').strftime('%Y-%m-%d')]
-    return date_list
\ No newline at end of file
+    tmp_list = date_list.copy()
+    for i in range(0, len(tmp_list)):
+        if len(tmp_list[i]) == 1:
+            tmp_list[i] = [datetime.strptime(tmp_list[i][0], '%Y%m%d').strftime('%Y-%m-%d'), datetime.strptime(tmp_list[i][0], '%Y%m%d').strftime('%Y-%m-%d')]
+        elif len(tmp_list[i]) == 2:
+            tmp_list[i] = [datetime.strptime(tmp_list[i][0], '%Y%m%d').strftime('%Y-%m-%d'), datetime.strptime(tmp_list[i][1], '%Y%m%d').strftime('%Y-%m-%d')]
+        elif len(tmp_list[i]) > 2:
+            tmp_list[i] = [datetime.strptime(tmp_list[i][0], '%Y%m%d').strftime('%Y-%m-%d'), datetime.strptime(tmp_list[i][-1], '%Y%m%d').strftime('%Y-%m-%d')]
+    return tmp_list
\ No newline at end of file