Abstract: With the rapid extension of HVDC transmission projects and high-speed railways in China, the situation that a DC ground electrode is placed closely to the high-speed railway has occurred from time to time. When a large current injected into the earth from the DC ground electrode, some of the DC current will flow into the high-speed railway system, which may cause DC bias of the transformers in the high-speed railway. In this paper, the analysis model of the DC current distribution with the high-speed railway integrated grounding system and the traction power supply system is established. The overall distribution of the DC current in the high-speed railway system is calculated. The currents flowing through the transformers in the traction substation, AT substation, section post and locomotive traction transformer are obtained. The influence of the spacing between the above stations, the positions of the DC ground electrodes, and the existence of the locomotive on the DC current flowing through the transformers is analyzed. The research results show that when the projection of DC grounding electrode is located in the traction substation or the AT substation, the DC current flowing through the transformer in the substation is the largest. When it is located in the section post or in the middle of two adjacent substations, the DC current flowing through the transformer will be reduced. The position of the locomotive has little effect on the DC current distribution along the high-speed railways.