In order to study whether the geo-acoustic signal can be used as a reliable earthquake precursor signal, a geo-acoustic sensing probe based on piezoelectric film is designed for seismic monitoring. The probe supports 0.1 Hz–7 kHz wide-band geo-acoustic signal acquisition, 19.073 μV voltage resolution, and amplitude consistency error less than 5.5% (0.47 dB). The probe passed 6 reliability tests including salt spray test, random vibration and package dropping, and applied to 178 stations including the Sichuan and Yunnan National Test Site for geoacoustic monitoring. Field observation experiments show that the stations around the epicenter can captured the underground geo-acoustic signals before and after the earthquake.