Abstract: The dynamic and mathematical models of the vehicle-seat-people suspension system with 4 degrees of freedom are built.Based on H_∞ robust control theory,an H_∞ controller is developed for this vehicle seat suspension system,and simulations are made with Matlab to compare and analyze the performance of H_∞ controller and the optimal controller designed for the vehicle seat system.Simulation results show that the vehicle seat suspension system with robust controller can reduce the vertical vibration acceleration of the seat by 50%~60% around the resonant frequency,and can effectively improve the comfort degree of driver compared with the optimal controller.It is also pointed out that the designed H_∞ controller is effective in system stability and robustness against some parameter fluctuations.