The invention discloses a hysteresis nonlinear servo motor system sliding mode control method, relates to the technical field of electromechanical control, designs a sliding mode state observer to observe the unknown state of the system, and solves the state variables of the hysteresis servo motor system such as servo motor angular velocity and angular acceleration , load angular velocity, load angular acceleration, hysteresis, etc. are difficult to measure directly, thus affecting the controller design; regard the remaining unknown parts of the system as disturbances, and use only one layer of Chebyshev neural network to estimate the unknown disturbances of the system, avoiding At the same time, the disturbance observer and state observer are designed to reduce the control difficulty and solve the estimation problem of the unknown disturbance of the hysteresis servo motor system; the sliding mode controller is designed to realize the accuracy of the hysteresis servo motor system by adjusting the tracking error and the sliding mode surface Tracking control, high precision, strong robustness, reduces the difficulty of the algorithm, unifies the model, and is more general.