The invention provides a permanent magnet synchronous motor traction system. During the application process in the rail transit field, when IGBT pulses need to be blocked and an inverter unit needs tobe powered off and enter idle running, a first three-phase contactor and a second three-phase contactor in a system reput-into-service unit are disconnected. When reput-into-service is required, thefirst three-phase contactor can be directly put into service if a permanent magnet synchronous motor is running at low speed, the reput-into-service is carried out, the second three-phase contactor does not operate, and a disconnecting state is maintained; and if the permanent magnet synchronous motor is running at a high speed, the second three-phase contactor can be directly put into service, amotor stator performs current limiting and voltage division by means of resistors serially connected with phases of the second three-phase contactor, or slow down the current rise rate by means of inductors serially connected with phases of the second three-phase contactor, and increases circuit time constant, thereby suppressing overcurrent or overvoltage faults caused by too fast rise of motor stator current and DC side bus voltage at the reput-into-service moment.