Single rod hydraulic cylinder is the most common hydraulic actuator in construction machinery.Due to the asymmetry of its two cavities area,the flow mismatch is caused.The electric cylinder drives the ball screw through the servo motor,which solves the disadvantage of the asymmetric area of the single rod hydraulic cylinder.However,due to the influence of the low power density of the motor,it is difficult to meet the requirements of low speed and large torque output under heavy load conditions.To solve the above problems,a hydraulic motor was used to drive the ball screw instead of the motor,and the closed-loop control of the new system was carried out through the segmented control mode of open pump valve.The results show that the new system can realize fast and accurate position control.The pressure,flow rate and speed of the push rod are exactly the same in the feed and return stages,and the system has no overflow loss.When the amplitude of sinusoidal signal is 50 mm,the bandwidth of the system is 0.8 Hz.The system has good anti-load interference ability.