Abstract: The rolling resistance of a pneumatic tire primarily depends on the deformation of the circumference between the tire and ground. There are three elements effecting the circumference: P_i, the inflation pressure of the tire; P_C, the pressure due to carcass stiffness and the specific pressure q that deformable ground can support. Based on all these situations of the circumference, this paper discusses the parameters which influences the rolling resistance and points out the methods for decreasing the rolling resistance in detail.