diff --git a/yuthon_hr_attendance/models/overtime_approval.py b/yuthon_hr_attendance/models/overtime_approval.py
index 7f1e7a8ca..7b19873cb 100644
--- a/yuthon_hr_attendance/models/overtime_approval.py
+++ b/yuthon_hr_attendance/models/overtime_approval.py
@@ -330,11 +330,9 @@ class OvertimeApprovals(models.Model):
                     ('text', '=', '上月额度继承'),
                 ], limit=1)
                 if existing_line:
-                    existing_line.write({
-                        'workday': workday,
-                        'legal_day': legal_day,
-                        'public_holidays': public_holidays,
-                    })
+                    existing_line.workday += workday
+                    existing_line.legal_day += legal_day
+                    existing_line.public_holidays += public_holidays
                 start_date = fields.Date.to_date(self.start_time)
                 end_date = fields.Date.to_date(self.end_time)
                 attendance_records = self.env['hr.attendance'].search([