Abstract: We have made the data collection and analysis system for recording microcracks in rock to study the three dimensional pattern of fracture and the dynamic properties of rock during pressurization. This system,with 8 channel data detection, records in real-time, from the initial microcracks to the final vibration waveform excited by the master fracture. The detected data are recorded by digital theharddiskofan IBM personal computerfor 286,386 personal computer) as well as transmitted to the disk. The sampling rate for each channel is 10 MHz.Collecting every acoustic emission events in the loaded rock sample with 8 channels by this system, mathematically modelling the AE event travel time, and taking the coordinates of the AE event hypocenter and the three components of P wave velocity as unknown parameters, we set up a set of residual equations for joint inversion, so that the three dimensional localization of AE event hypocenters can be completed under variable velocities, which will lay foundations for the research on rock fracture clearly.