Aimed at the control problems for passive electric hydraulic servo system, the high-order integral sliding mode control method was proposed. The request of tracking controller for the desired trajectory of higher order derivatives could be reduced by the integral sliding mode, and the chattering problem of the conventional sliding mode variable structure control was effectively suppressed. The conservative design of the controller parameters could be reduced by the uncertainty of CMAC neural network online learning system. The control method was used in electric hydraulic servo system, and simulated. The results show that the control scheme has better control performance, and can effectively suppress chattering of the system. 