Abstract: By synchronously monitoring the rail ground potential of the tram and the on/off potential of the pipeline, the stray current interference of super capacitor energy storage power supply tram on the buried steel pipeline was studied. The results showed that when the tram was charged at the station, the rail ground potential had obvious positive and negative deviation, and stray current was absorbed and discharged through the rail. When the pipeline was affected by the stray current of the tram, the power on potential of the pipeline was -7.060 -3.023 V_CSE, and the power off potential was -1.219 --0.143 V_CSE. The power off potential at many places along the pipeline was higher than -0.85 V, which did not meet the cathodic protection criteria, and the interference influence range was far greater than 97 km. The pipe section close to the tram and the pipe section far away from the tram were areas where stray current flowed in and out of each other, and the interference effect of the pipe section close to the tram was revelatively far. When the tram was charged at the station within the power supply range of the traction substation, the ground potential of the rail rised, and the stray current from the rail flowed into the pipe section near the tram. The stray current flowed along the pipeline to the direction far from the tram, and flowed out in the pipe section far from the tram.