Based on ADAMS and NASTRAN, a rigid-flexible coupling dynamic full vehicle model was established. A virtual test rig was also built up by using ADAMS/Vibration to analyze the vibration responses and transfer characteristics of the suspension system motivated by middle-high frequency road excitations. To improve the vibration isolation capability of the suspension system，the effects of the subframe, twist beam and rubber bushings of the chassis/suspension system with the vehicle vibration was analyzed. Finally, through adopting the ADAMS/Insight DOE technology, the researchers proposed the sensitivity analyses of several key rubber bushing stiffness, and the optimization of the bushing in the environment of ADAMS/Insight. By changing the bushing stiffness, the vibration performance of the vehicle was improved. Simulation results indicated that the vertical acceleration root mean square (RMS) decreased from 477.9 mm/s2 to 454.2 mm/s2 , by 5% in the whole research frequency spectrum.