Abstract：Acoustic emission(AE)，which is produced by the micro-cracks occurrence or growth，is a ubiquitous phenomenon associated with brittle fracture in many materials. AE technique can be used to monitor the micro-cracks development in the rock sample continuously and in-real-time，which is better than other methods. AE location technique is employed to study rock failure process. It is investigated using granite samples with different precut cracks；and AE sensors are mounted on the surface of the sample. A Geiger location algorithm allows AE event location from first arrival times to be determined by AE sensors，which is applied to study the crack initiation and propagation process，also to analyze the crack spatial evolution mode with stress changing during the total loading process. The experimental results show that AE activity represents different characters with stress-strain changing during the total loading process；the quantity of the AE events is very little from the initial loading to crack initiation；when the initial crack generates，AE events apparently increase；AE events are in quiet period after crack initiation up to the time before crack propagation；AE activity sharply increases from crack stable propagation up to crack unstable propagation，especially in crack unstable propagation step，AE events reach to the most quantity in the division strain. There is “void space” of AE events during the AE location results；the “void space” of AE events is the position of macroscopic crack breakthrough，which can be used to predict the crack breakthrough position of rock samples. Meanwhile，AE location results are also direct reflection of interior stress field propagation process. AE location results also reflect directly the spatial position，direction and spatial curved face of crack propagation in the rock sample，which is very significant to study the mechanism of rock failure.
