Abstract: The mechanical properties and acoustic emission evolution process of limestone under the action of high temperature load were investigated by combining the methods of acoustic emission technique and uniaxial compression test. The temperature varies in the range of 100，200，400，600 and 800 °C. Acoustic emission characteristic parameters and the mechanical parameter under different temperatures were analyzed. The results show that the temperature affects the acoustic emission phenomenon of limestone obviously, the peak stress decreases as the temperature increases and drops by 50 percent from 600 °C to 800 °C, but the peak strain changes not obviously; the average accumulative ring-down count increases as the temperature increases before 400 °C but reduces unceasingly as the temperature increases after 400 °C； the specimens present obvious plastic failure characteristic after 600 °C, the accumulative ringdown counts decrease obviously and conform to the stress-strain curve.

Key words: high temperature, limestone, compression fracturing, acoustic emission, accumulative ring-down count