The invention discloses a four-rotor flight control method based on the fractional order saturation function power switching law. A system is split into two subsystems through utilizing the backstepping control method, the traditional backstepping control method and the sliding mode control method are utilized to design sub-control laws satisfying the Lyapunov theorem for the two subsystems, specifically, the backstepping control method is to inherit integrity and unity, and the sliding mode control method is to improve robustness and the anti-interference ability. When the sliding mode control method is utilized, the fractional order saturation function power switching law is introduced to improve performance of a controller, trembling is suppressed, fast response of the flight control ofa four-rotor drone is guaranteed, through adjusting saturation function parameters, nonlinear characteristics of the controller can be further improved, trembling in controller output is filtered, and smoothness of the controller is improved.