When the oil immersed transformer fails, it will cause abnormal vibration of the iron core and winding, excessive temperature rises and transmission to the box. In order to simultaneously monitor the vibration and temperature status of transformers during operation, an RFID sensor based on dual antennas is designed, which integrates temperature and acceleration sensor chips. In addition, an "L" shaped metal reflector is added to enhance the radiation efficiency. The accuracy of the RFID sensor was tested in the laboratory, and the results showed that the test errors for vibration and temperature were only 0.7% and 1.6%. Finally, OFPSZ-150000/220 transformer is taken as the experimental object for field monitoring. The results show that the vibration signals of the transformer box monitored by RFID sensors are mainly concentrated in the range of 100~500 Hz with 100 Hz as the fundamental frequency; The temperature of the box is higher when it is closer to the middle and lower when it is closer to the edge. The experimental results show that the measured data is very close to the field data, the measurement errors of acceleration and temperature are only 6.25% and 1.9% which proves the reliability of the RFID sensor.