Abstract: Aiming at the imprecise nonlinear systems such as flapping-wing aircraft, a method of attitude control for flapping-wing aircraft is proposed. Due to the disturbance caused by the complex environment and the uncertainty of the system, a dual loop tracking and adjusting attitude control based on sliding mode variable structure control is implemented, in which Lyapunov function is also introduced. In the flapping wing state, the goal posture such as pitch, yaw, roll and so on is achieved smoothly. The buffeting problem caused by the switching function of the traditional sliding mode control is overcome by the inner and outer loop design. The MATLAB simulation results show that the control method can rapidly reduce the Euler angle deviation and improve the dynamic response characteristics. It has good robustness and improves the accuracy of attitude adjustment.