Abstract：Based on investigation of acoustic emission(AE) characteristics during deformation and failure process of coal specimens under different stress paths，the general uniaxial compression，triaxial compression and confining pressure reduction experiments were performed by RMT–150B rock mechanics test system，in which coal specimens were from Gengcun Mine，Yima Mining Group with outburst proneness. Test results indicate that the AE characteristics of coal specimens were different in deformation and failure process under different stress paths. In experiments of general uniaxial compression，AE events of different degrees took place on every stage. Compared with experiments of uniaxial compression in triaxial cylinder，the values of AE counts and energy were obviously larger and the momentary values of maximum AE counts and energy at failure were approximately equal. In experiments of general triaxial compression，AE events were fewer before yielding and increased obviously then. At stage of post-yielding，AE events were quite active and enhanced rapidly，which was a sign of failure portent，and the value of AE counts and energy reached maximum at failure instantly. In experiments of confining pressure reduction，AE events were fewer，because the specimens were in elastic stage before confining pressure was relieved. With decreasing confining pressure and friction provided by positive stress，the inner zones of samples with low strength yielded to fail gradually and formed microcracks. AE events occurred in small amount in previous yielding stage，while AE counts and energy were quite active and enhanced rapidly in late yielding stage，which was also a sign of failure portent，and AE counts and energy reached maximum value and failed instantly. Compared with general triaxial compression，the maximum values of AE counts and energy were much larger；and the results indicate that the failure of coal samples in experiments of confining pressure reduction were more violent. In experiments of uniaxial compression in triaxial cylinder，general triaxial compression and confining pressure reduction，AE totalized counts and energy were approximately identical.
