This paper conducts experimental investigation on acoustic emission(AE) characteristics of coal rock at uniaxial and triaxial compression by MTS815 rock mechanics test system. The results show that the variation of AE has tendency effect at uniaxial compression and confining pressure experiments. We indicate that AE signal decreases significantly in the elastic stage, and the relatively quiet period of AE before the specimens failure is not obvious under confining pressure. The AE amplitude distribution with time and its envelope line can indirectly reflect the trend of stress. The AE events peak stress and elastic modulus decrease with the temperature increase, and the value of m which reflects the cumulative distribution of amplitude increases as the confining pressure rises. The results also show that the AE frequency distributes in three frequency domains, and the proportions of dominant frequency significantly increase while the specimens are broken.