Abstract: Targeting the phenomenon of metro vehicle large noise during operation, the wheel out-of-roundness and the rail roughness at different positions on track are measured and analyzed. Research discovers that the test line rail roughness is significantly higher than the limit value in international standard ISO 3095:2013, and the higher rail roughness on curve is the main reason for larger metro noise. After wheel reprofiling, due to the reprofiling operation and process influence, the low-order polygon and long-wave roughness of the wheels of the Tc (trailer car with cabin) car and Mp (motor car with pantograph) car decrease, while the surface roughness at short-wave increases significantly, and the wheel roughness of the Mp car becomes worse even more, resulting in sharp increase of vehicle noise. Therefore, only reasonable wheel/rail roughness maintenance strategies and effects can reduce metro vehicle noise.