A robust fault-tolerant control method is proposed for the quad-rotor Unmanned Aerial Vehicle(UAV) under input constraints with actuator failure and disturbances.Firstly, the position model and attitude model of quad-rotor UAV including actuator fault, input constraints and external interference are established.Then, the position loop and attitude loop are analyzed respectively, and the virtual control command is filtered by sliding mode filter.The uncertainty is estimated by fuzzy system approximation method, and the robust fault-tolerant control law is designed.Finally, the stability of the position loop and the attitude loop is proved.The simulation results show that the proposed robust fault-tolerant control method can quickly and accurately track the command signal under input constraints, and has better control effects than integral sliding mode fault-tolerant control law, which realizes the full-state robust fault-tolerant control including actuator fault and external interference.