A ball screw regenerative shock absorber was designed for the relief of the vehicle vibration and the energy recovery of the vehicle vibration. The effect of its main parameters on the suspension system was numerically analyzed. According to the principle of the ball screw regenerative suspension system, a mathematical model of the ball screw regenerative shock absorber was established regarding the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut. A suspension dynamic model based on the ball screw regenerative shock absorber was developed combining the road model and the two-degrees-of-freedom suspension dynamic model. Using a triangle pulse input condition and a random road input condition, through changing value of parameters with an interval of 2% of the initial value, the influences of parameters, including the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut, on the ball screw suspension performance were investigated. Finally, the parameter sensitivity was studied using the one parametric variation method. It was found that the most significant factor affecting the suspension performance is the screw nut radius, followed by the screw lead, while the effects of the ball screw's moment of inertia and the motor's moment of inertia are less significant.