diff --git a/backend/flask_app.py b/backend/flask_app.py
index 8795808..1fd4997 100644
--- a/backend/flask_app.py
+++ b/backend/flask_app.py
@@ -319,11 +319,11 @@ def attach_common(conn, resource, items):
 def monthly_finance(conn, tenant="科普·无界"):
     from datetime import date
     today = date.today()
-    # 12 months: 9 before + current + 2 after
+    # 6 months: 3 before + current + 2 after
     from dateutil.relativedelta import relativedelta
-    start = today + relativedelta(months=-9)
+    start = today + relativedelta(months=-3)
     months = []
-    for i in range(12):
+    for i in range(6):
         m = start + relativedelta(months=i)
         months.append(m.strftime("%Y-%m"))
     data = []