The existing shell model is accurate in the frequency band of 0~500 Hz， making it highly suitable for tire vibration analy? sis. However， the modal properties of the tire belt cannot be obtained separately and the freedom as well as the number of parame? ters required by the model increases， because the shell model couples the tire belt and sidewall. Therefore， this shell model was im? proved in this paper. The shell model for simulating the tire belt remained unchanged， whereas， by using the method for approxi? mating the sidewall used in the ring model and plate model of tire， the two-dimensional shell model for simulating the tire sidewall was replaced by an elastic foundation to simplify the boundary conditions of the tire belt and reduce the number of parameters related to the tire sidewall. The solving method for the improved shell model was developed to calculate the modal frequency and the modal shape of the tire belt. The validity of both the improved shell model and its solving method was demonstrated by an ex? periment.