The continuous development of hollow wear on the wheel tread of railway vehicles can decrease vehicle stability. In order to improve vehicle stability and ensure traffic safety, an optimization method for vehicle stability is proposed. In this method, the mapping relational model between the hollow worn parameters and the equivalent taper is established to obtain the hollow worn parameters characteristics corresponding to the low equivalent taper, and then the vehicle dynamics parameters are optimized to improve the evolution results of the tread hollow wear. Finally, the vehicle stability is improved. After optimization using this method, the wheel equivalent taper of the vehicle running 129,000 km decreased by 16.39% compared to before optimization, and the maximum lateral vibration acceleration of the frame also decreased by 32.02% compared to before optimization. In summary, this method can effectively improve vehicle stability and provide a reference for solving the problem of stability degradation caused by tread wear on high-speed trains.