In order to overcome the influence of unknown actuator faults on the flight of quad-rotor UAV formation, an optimal cooperative fault-tolerant control law based on dynamic programming is proposed.The quad-rotor UAV model is established, and the optimal cooperative control law is designed based on dynamic programming.RBF neural network is used to approximate the optimal performance index function, and an adaptive law is designed to estimate the unknown actuator fault.The optimal cooperative fault-tolerant control law can realize the high-precision control of UAV formation flight.The comparative simulation has verified that the designed optimal cooperative fault-tolerant control law has better formation control effect, and the maximum trajectory tracking error of formation flight is only 0.04 m, which shows that the control accuracy is high.The designed adaptive law has better fault estimation effect, and the maximum estimation error is only 0.05 N·m, which realizes the safe and stable control of quad-rotor UAV formation.