The stiffness of throttle valve directly affects the opening of damping hole and the damping characteristics of shock absorber. In order to analyze the influence of the number and material of valve plate on the stiffness of the throttle valve, different calculation models were established. The finite element analysis method was used to calculate the deformation of the valve group under the action of the oil pressure. The results show that under the same thickness, the stiffness of the valve plate decreases and the opening speed of the throttle valve increases with the increase of the number of valve pieces or the decrease of the elastic modulus of the valve material, as a result, the damping force of the shock absorber is reduced.