In this paper, in order to investigate the effect of the acoustic emission sensor on rock fracture monitoring, biaxial loading experiment of granite with holes was carried out. Selecting two types of sensor: R6α (narrow band) and Nano30 (broad band) to simultaneously monitor rock failure process, the similarities and differences of the time-frequency characteristics received by two types of sensor were analyzed. The applicability of two types of sensors from the working frequency band and sensitivity is discussed in this paper, and then the selection principle of AE sensors in rock fracture monitoring is put forward.Study results show that in time domain, the energy evolution pattern of acoustic emission signals received by two types of sensor is consistent. In frequency domain, the main frequency of R6α sensor received signals is concentrated in 33~110kHz, while the main frequency of Nano30 sensor received signals is uniformly distributed within 0 ~ 500kHz. The signal received by R6α narrow frequency sensor has high intensity and large data amount, which can insulate the interference of noise signal in other frequency bands. So it is suitable for analyzing the timing pattern of rock rupture. Nano30 broad band sensor can guarantee signal integrity in frequency, and can be used to analyze acoustic emission signal waveform and frequency characteristics of rock.