The impact and vibration of vehicles often occurs in three directions along or around axes, which need multidimensional vibration isolation. If the technology was applied on one dimensional vibration isolation into multidimensional vibration isolation simply, the vibration isolation device would interfere. So a multidimensional vibration isolation device of vehicles was developed. It is composed of two Stewart mechanisms: down platform and up platform. The two Stewart mechanisms with six degrees of freedom lead to the same degrees of freedom of the device. Damping and springs installed in joints of the two Stewart mechanisms isolate the vibration of vehicles. Dynamics simulations by ADAMS show that when the down platform is given an impulse, 6 accelerations of up platform are less than those of down platform obviously, and they decline rapidly. The shocking time, damping coefficient, stiffness coefficient of springs were simulated.