Electro-hydraulic servo system has the characteristics of high nonlinearity and model parameter uncertainty, which makes it difficult for hydraulic cylinder displacement tracking control. High-order sliding mode is a variable structure nonlinear control method. Using this method can achieve robust control and attenuate chattering for the system, which is very suitable for the control of electro-hydraulic servo system. However, the high-order sliding mode also has the problems that the parameters of controller are difficult to set and the system response speed is slow. For this reason, a composite control strategy based on adaptive high-order sliding mode and proportional feedback was proposed. An parameter adaptive adjustment algorithm was proposed based on time delay control to solve the problem that the control parameters were difficult to set. Using this method,the asymptotic stability of the system was ensured and the chattering amplitude of the control signal was reduced. The proportional control was added on the bas is of adaptive high-order sliding mode control to improve the response speed. Finally, the simulation model of electro-hydraulic servo system was established. The simulation results show that the adaptive high-order sliding mode can further reduce the chattering amplitude of control signal,the hydraulic cylinder chattering caused by control signal is effectively suppressed;when the proportional control is added, the response speed of the system is greatly improved, and the displacement tracking error is also significantly reduced.