Abstract:Acoustic emission(AE) characteristics of outburst coal samples are studied during the failure process in uniaxial compression under the stiffness test machine(MTS). The AE rate,ringdown-event ratio,cumulative counts,stress-strain levels,time and the relations among them are also analyzed. The results show that AE characteristics of coal samples depend strongly on different failure phases during the loading process of compressive tests,and the failure process is divided into five phases according to stress-strain curves and AE characteristics. The ringdown-event ratio is related to the change of energy in the coal,which represents the trend of AE curves during the failure process more accurately. So it can be used as one of the main forecasting parameters of coal and rock dynamic catastrophe. Elastoplastic phase(III) is the main phase,in which AE accumulative counts increase more,about 35.35% of its total counts. When the stress-strain curve is near the peak,the AE accumulative counts curve reaches a plateau,which means that there is a relatively inactive period of AE. The pre-peak relatively inactive period in other rocks also exists in the originally damaged coal,but the period of the damaged coal is shorter. The sharp increment of AE curves and the relatively inactive period before peaks can be seen as the symptoms of the coal peak value destruction to forecast the coal-gas-outburst in the coal mine.