The acoustic emission evolution process of Jiaozuo sandstone with 20 ℃-1 200 ℃ temperatures is studied using acoustic emission (AE) test under uniaxial compression. By analyzing AE parameters and the mechanical properties of sandstone after high temperature

the AE characteristics of sandstone under different temperatures and different loading stages are explored. The results show that temperature has little effect on the acoustic emission of sandstone when temperature is less than 400 ℃. The AE ring-down accumulation counts change rapidly both at about 100 ℃ and 600 ℃ temperatures. It is shown that 100 ℃ is the threshold of crack growth for sandstone; and the internal structure composition of sandstone changes after 600 ℃; and acoustic emission phenomenon is very obvious. From 600 ℃ to 1 200 ℃

obvious brittle-plastic transition appears in sandstone. At the same time

the emergence of acoustic emission signals is delayed and the growth rate of acoustic emission signals rises because of high temperature. Sandstone releases intensive acoustic emission signals and presents plastic failure characteristics after 1 200 ℃.