Abstract: When high-speed rail intersects with pipelines in parallel, its power supply system will cause AC interference to the pipelines, leading to pipeline corrosion and even breakdown of the anti-corrosion layer. Due to the continuous movement of the train, the AC interference on the pipeline is constantly changing, which poses difficulties for the design of interference mitigation. The influence of high-speed train position on pipelines was studied using numerical simulation methods. The results show that: (1) The AC interference on the pipeline is mainly generated by the current inside the rail, and due to a large amount of current leaking from the rail to the ground, a "current imbalance" occursed. (2) During the operation of the train from TPSS to AT2, the peak AC voltage occurred at the starting, ending, and middle points of each AT section. (3) Due to the presence of intersections and the "positional imbalance" between CW, AF, and tracks, peak AC voltage could also occur at intersections. (4) The AC interference on the pipeline decreased as the rail leakage resistance increased, because as the rail leakage resistance increased, the current leaked from the rail to the ground decreased. (5) On site testing was conducted on an actual gas pipeline in the Beijing area. The measured AC voltage of the pipeline on site was basically consistent with the calculated value.