Given the uncertainty of the severity of stray current on the corrosion area of buried pipelines along the subway line, a three-dimensional finite element analysis model of stray current is established to study the distribution of stray current under the operation mode of subway upward and downward trains and the dynamic changing process of the cathode and anode area on the buried pipeline. Considering only the influence of anode stray current, the interference area and degree of the buried pipeline during train operation are judged by comparing different models. The results show that when the two trains are running in opposite directions at the same time, the interference area of the buried pipeline is mainly distributed on both sides, and the interference area is symmetrical concerning the central position of the pipeline. When the upward train starts 18，37 s and 55 s earlier than the downward train, the areas with strong interference degrees on the buried pipeline are mainly distributed on the right side of the pipeline. Among them, when the upward train starts 55 s earlier than the downward train, there is a large interference current density on the buried pipeline, up to 18 A/m² . In the later protection of subway stray current, corresponding measures can be taken for the serious interference area of pipeline in combination with finite element model.