The sensitivity of ride comfort performance to the vehicle elastic component is studied in this paper, including suspension spring, suspension rubber component, seat and tire. Firstly the quarter ride dynamics model considering the elastic characteristic of vehicle and the friction and hysteresis characteristic of suspension system of one passenger car, having three degrees of freedom, is established. By the MatLab/Simulink simulation, the vibration responses of seat and floor under random input are achieved and some objective evaluation indexes of ride comfort are calculated. Furthermore the sensitivity analysis for objective evaluation indexes on key parameters which influence ride comfort is carried out with Parameter Sensitivity Analysis theory and some conclusions are summarized.