According to the characteristics of highspeed electric multiple units (EMUs), aiming at the defects of the existing axle temperature monitoring technology, a new highspeed EMUs axle temperature monitoring system based on SAW RFID technology has been proposed in this paper. SAW tags are used to realize the passive temperature monitoring and DSP chip TMS320VC33 is used as the main controller to control the receiving and transmitting of RF chip NRF905. The principle of SAW RFID technology is introduced and the designs of reader and control software are presented. The system test are carried out. The results show that the system can accurately monitor the axle temperature condition of highspeed EMUs in realtime，and it plays an important role in ensuring the safe operation of highspeed EMUs.