Aiming at the influence of the change of control parameters and the interference of external environment of the four-rotor UAV, the motion control of four-rotor UAV is studied in this paper. First of all, the transfer function is obtained by establishing the dynamics model of UAV, then, the fuzzy theory and cascade PID control algorithm are combined, the last time, the fuzzy controller is used to modify the control parameters, the dynamic performance of the system is further optimized and the control effect of the UAV is better. The height and attitude Angle model of UAV is established by the Simulink, meanwhile, the control effect between cascade PID and fuzzy-cascade PID was compared and analyzed. The simulation results show that the dynamic performance of UAV will be better with fuzzy-cascade PID controller, the adjustment time is shortened by 0.51~0.93s, the overshoot is reduced by 10% to 13%, the oscillation of steady state process is reduced and the whole process tend is smoother, meanwhile, it has better anti-interference performance.