Aiming at the position control system of active suspension electrohydraulic servo actuator with uncertain load mass and load force, the internal model control method was used to control the position of the actuator. Firstly, according to the characteristics of the system, the linear mathematical model of the electrohydraulic servo actuator position control system was established, and then the internal model controller was designed based on the model. In order to verify the control effect of internal model controller, the simulation analysis and bench test were compared with PID controller. The step signal was used as the input signal for simulation analysis. The simulation results showed that the unit step response of the system under internal model control was fast, stable, no overshoot, and its dynamic characteristics were better than that of PID control. When the system was disturbed by external interference, it can return to the steady value more quickly and stably than PID control. The bench test included changing the frequency of sinusoidal input signal and changing the load quality. There were three kinds of experimental schemes. The experimental results showed that when the frequency of sinusoidal input signal was increased from 0.1Hz to 2Hz, the tracking performance of the system based on internal model control had no obvious change, while the tracking performance of the system based on PID control was obviously deteriorated when the sinusoidal input signal frequency was 2Hz; the test results of changing load quality showed that when the load quality was changed, the system based on internal model control had no obvious change. The variation range of tracking error was obviously smaller than that of PID control. The tracking response performance of electrohydraulic servo actuator position control system based on internal model control was better than that of PID control, and can meet the requirements of active suspension system.