Abstract: Based on the contact angle curve reverse repulsion method，the tread of 100% low floor tram running in Nanhai District of Foshan City is optimized. Compared with the original tread，the optimized one increases the restore ability of the independent rotting wheel set，improves the wheel/rail contact state and reduces the wheel/rail contact stress. A calculation shows that the optimized tread improves the dynamic performance of the vehicle，and the wear depth of the optimized tread is less than that of the prototype tread.