Abstract The mathematical model of four degrees of freedom vehicle suspension was established, based on that, built the vibration differential equation and road excitation matrix; the frequency response function and root mean square value which could evaluate response variable were derived; in the case of constant pavement condition and running speed, the simulation in time domain was carried out, the effect tendency of variation of suspension damping to three evaluating indexes of suspension control was obtained, it provided basis for both suspension damping matching with shock absorber damping and research on vehicle ride.