Abstract: Based on the acoustic emission (AE) location technology and moment tensor analysis method， the experiment study of fracture mechanism and time and space distribution characteristics of the cracks during fracture process of rock specimens under uniaxial compression was conducted. The acoustic emission events with different fracture mechanisms can be used to identify the forms of the cracks directly with the help of CAD software. The results show that shear failure was more than other failure types in granite sample under uniaxial loading. However， the form of microcrack that may have no fixed proportion is determined by its mechanics environment. It is a phenomenon that， the brittle fracture of granite does not agree with the Griffith strength criterion where the fracture is considered to be caused by tensile in brittle materials， thus clarifying the limitations of the Griffith strength criterion. AE generated by different sample types fracture， which is independent of the stress level， has similar trend in the increasing stress during uniaxial loading of granite.

Key words: rock, acoustic emission(AE), moment tensor, crack, fracture type