In the investigation,by simplifying the tire structure,a corrected tire brush model is constructed and a longitudinal force expression is set up.Then,by analyzing the interaction between tire and ground,the kinetic and static friction ellipses are established to solve the longitudinal forces from attachment and slip regions,and the rela- tionship between the two longitudinal forces is discussed.According to the stiffness difference of tire tread and shoulder,the longitudinal forces of the tread and the shoulder are solved under the influence of stiffness on contact patch length being considered.It is found that the corrected tire brush model accords well with the magic formula and the experimental results when the slip rate is between 0.0 ～0.2.Besides,the proposed method helps to opti- mize the design of tire.