Abstract: Aiming at the poor control performance of electro-hydraulic force control system of PID caused by strong time-varying hydraulic parameters and unknown external interference, and combining the advantages of active disturbance rejection control (ADRC) in active estimation and disturbance compensation, the electrohydraulic force control system of based on ADRC was designed. The mathematical model of the hydraulic part of baler was established by the power bond graph method, and its order was reduced by the zero point configuration method, and then the first-order linear ADRC controller was designed. AMESim and Simulink software were jointly used to simulate the system, and the responses of PID and ADRC systems to different command signals under the interference were analyzed, and the control performance and anti-interference ability of the designed system were verified. The results show that compared with PID control, in the case of the same external interference, the response of ADRC system to the step signal has no overshoot and oscillation, and the response time is reduced by 50%, and the relative tracking error of sinusoidal signal is reduced to 2.4%. The control performance of ADRC system remains basically unchanged under the condition of increasing interference, showing strong robustness.