Abstract: In view of the nonlinear and time-varying characteristics of a flight simulation turntable servo system, we propose a high-order sliding mode control based on Lyapunov function. Its controller is based on the reach conditions. High-order sliding mode control is applied to variables, which have a discontinuous switching term of higher-order differential, thereby ensuring that the system achieves the strong robustness of the traditional first-order sliding mode control while reducing the chattering of sliding mode control. We use the equivalent input disturbance estimator to estimate the compensation error interference, thereby further improving the precision of the control system. The stability of the system is proved by Lyapunov stability theorem. Simulation results show that the design of the second-order sliding mode controller added to the EID estimator can effectively weaken the system's chattering problem, thereby improving the robustness of the system.