Abstract: ［Objective］ Due to the complex installation environment of the train in actual application, the balise antenna is subject to varying degrees of interference, sometimes even affecting its normal operation. Therefore, it is necessary to carry out the research on balise antenna interference. ［Method］ The signal equipment restart failure encountered by the balise transmission module (BTM) on Nanjing Metro Line 7 during the commissioning stage is taken as the research object. Through systematic investigation, three potential factors of interfered equipment, interference path and interference source are analyzed one by one, and finally the root cause of the fault is accurately identified. ［Result & Conclusion］ After careful handling of the fault′s root cause, the restart fault of the BTM on Nanjing Metro Line 7 trains is successfully solved, providing valuable experiences for subsequent design work. In the design and manufacturing process of metro vehicles, it is imperative to pay great attention to electromagnetic interference issues. Preventing the generation of interference sources from the source, and designing isolation measures for the interference path reasonably can ensure the stable operation of trains in complex electromagnetic environments.