The quad-rotor UAV control system is not only complex, but also susceptible to external interference, and has poor robustness.In order to enhance the controlling precision of the quad-rotor UAV, the sliding mode variable structure control method is adopted in this paper.The quad-rotor UAV dynamic mathematical model, motor model and wind field disturbance model are built up.Then, Matlab is utilized to establish SMC controllers, and appropriate parameters and methods for vibration eliminating are selected.Therefore, the altitude and attitude of the quad-rotor UAV can be controlled.The experimental results show that the SMC controllers have fine dynamic performance and anti-disturbance performance.