This paper adopts a method of tire modeling which uses tire experimental modal parameters which are obtained by means of radial and tangential excitation. The action force from ground to tire are treated as inputs for model. Calculations of static properties are dealt with transfer functions at 0 frequency. An iterative algorithm is used to work out the vertical properties, contact length and vertical and frictional force distribution in longitudinal direction. The vertical vibration characteristics under 300Hz of a pre-loaded tire are given, and that of the system composed of wheel, suspension and car body are analyzed by using modal synthesis method. The study shows the feasibility and advantages of this method.