In order to explore the dynamic monitoring ability of surface crack propagation based on radio frequency identification(RFID) tag sensor, a new crack propagation test method is designed by using microstrip tag antenna as crack sensor and its backscattered signal as crack growth characterization parameter. In this method, the actual size of surface crack in propagation is obtained by the crack front marking technique, and the relationship between the size of surface crack and the phase of backscatter ed signal is established. The experimental results show that the sensor can sense the crack growth of 5.646 mm2, theoretically it can achieve a monitoring sensitivity of 0.195 (°)/mm2, achieving the purpose of dynamic monitoring.