Windshear is a red unsafe event monitored by FAA, and understanding the distribution characteristics of windshear events can help the industry to carry out flight operation quality monitoring more effectively. In this paper, we analyzed the QAR data of flights triggering wind shear alerts in the past two years. From the warning altitude, more than 80% of RWS events occurred at low altitudes below 200 ft. From the distribution of warning events in flight phases, more than 65% occurred in the approach and landing phases and were mainly of RWS type, while less than 35% in the takeoff and climb phases and were mainly of PWS type. The significant variability in the distribution of warning events during takeoff and climb and approach and landing phases is related to the aircraft weight, airspeed, pitch attitude difference and the pitch and scan mode settings of the weather radar during the different phases.