Abstract: Aiming at problems of the stray current leakage corrosion in urban rail transit DC traction power supply system and the frequent operation of rail potential limiting device in urban rail system, the influence of regenerative braking energy utilization on rail potential in DC traction power supply is analyzed. Through establishing a distribution model of stray current and rail potential during multi-train dynamic operatin, the distribution law of stray current and rail potential is simulated, analyzed and compare with the distribution of train power. It is concluded that the greater the distance utilization of regenerative braking energy, the greater the increase of rail potential. Finally, through a comparison between the application of train braking current, the maximum stray current and the maximum rail potential, the proposed method is further verified.