Aileron is one of the important control surfaces of civil aircraft. Its main function is to generate aircraft roll moment and change the course of aircraft. The control system of modern medium and large aircraft mostly adopts servo actuator-control surface device. When the control surface is subjected to hinge torque, the actuator is also loaded accordingly. Taking the aileron actuator of civil aircraft as the research object, based on the test flight data and the load calculation model of the actuator on the main control surface, a method for dividing actuator load events based on mean value was proposed. The results show that the event partition method is effective and reflects the difference of load mean between different flight events. Through rain flow treatment on the load history of 14 000 flight actuators, the corresponding load spectrum, load amplitude and mean distribution histogram were given, and the relevant distribution rules were summarized. The fatigue load spectrum and its corresponding distribution law are of great significance to the life calculation in engineering practice.