The present invention discloses a method for triggering a status report of automatic repeat request. When a receiver acknowledged mode radio link control entity detects that received radio link control layer PDUs are missing, a timer T1 is set. When the timer T1 is running, new timer is not set even if a new missing radio link control layer PDU is detected. When the timer T1 is running, if the receiver acknowledged mode radio link control entity has received all missing radio link control layer PDUs which are detected before setting T1, the timer T1 is stopped. When the timer T1 times out, the receiver acknowledged mode radio link control entity triggers the status report.