Abstract: The pneumatic tire is an important component of a vehicle.Its dynamicperformances have great effect on the whole automobile.Based on the real structure of a tire,authors of this paper have founded a composite material tire model.which, consistes of carcass plies,reinforcement layer and rubber.Also, the differential equation of a pneumaticmeridian tire has been developed and the mode shapes of the firecorresponding to the test result been obtained.