Abstract: The vibrate-isolation analysis in practical engineering was simplified with the single degree of freedom vehicle bridge system vibration isolation system. The dynamic equilibrium equation of the fractional derivative order car-bridge model of vibration isolation was presented. Without considering the excitation response produced by micro-variation of bridge, trigonometric function was used to calculate the model. The vehicle motion amplification coefficient and transmission ratio were obtained and the effect of parameters were analyzed. And the vibration isolation static displacement was discussed under the condition of no damping and arbitrary isolation efficiency in practical engineering.