A power chuck reliability test bench with torque loading hydraulically was designed to achieve loading torque dynamically using electrohydraulic proportional pressure relief valve as the control valve. The mathematical model of the electrohydraulic proportional pressure relief valve was gained using the MATLAB system identification toolbox, and the system model was therefore established. In order to ensure the accuracy and stability of torque loading, two control schemes were discussed and simulated using MATLAB. The simulation results indicate that loading system is capable of loading torque stably with regular PID control and it is more robust with fuzzy PID adaptive control.