In view of the problems that the order of the observer is too high when the traditional active disturbance rejection control(ADRC) is applied to the electrohydraulic position servo system,resulting in many observation variables,heavy burden,serious phase lag and large system response overshoot of the state observer,the reduced order ADRC scheme was adopted to deal with them.Taking the position information of the system as known to reduce the order of the observer,the observation lag can be effectively weaken,the overshoot of the system can be reduced,the anti-interference ability of the system can be improved,the parameters to be adjusted of the controller can be reduced,and the stability of the system can be improved.MATLAB and AMESim were used for joint simulation.The results show that compared with the system with traditional ADRC,the overshoot of the system with this control strategy is reduced by 798%,and the adjustment time is shortened by 227%,by which the control performance of the electro-hydraulic position servo system can be improved and the system has better disturbance rejection performance.