Abstract: Based on the vehicle overvoltage fault records and third rail power supply of the track breakage area, the causes of the overvoltage fault of the vehicles on Beijing metro Fangshan Line are analyzed. Four solutions are proposed, including changing the bus penetration form, optimizing the control function of the traction system, improving the passing state under ATO (automatic train operation) mode, and changing the access mode when the vehicles turn back. From the perspective of operation, the characteristics of the four solutions schemes are discussed. It is concluded that the measure of optimizing traction system control function suits the site condition better, and hidden dangers of operation are eliminated through implemention of the scheme.