In order to improve the attitude control accuracy and anti-disturbance performance of the quad-rotor UAV,the disturbance observer and the extended state observer are combined,and a sliding mode anti-disturbance control approach based on dual observers is proposed.First,the disturbance with part of the known information is described by the exogenous system model and estimated by the disturbance observer;then the extended state observer is used for the estimation of the complex nonlinear differentiable disturbance;then a sliding mode control law is designed to compensate for the disturbance estimated by the dual observers to achieve attitude control;finally,the stability of the system is proved by the Lyapunov theory.The simulation results show that this method has higher tracking accuracy and better anti-disturbance ability than traditional PID control.