Abstract: To study thermal-mechanical properties of carbonaceous limestone, we carried out acoustic emission(AE)monitoring test of limestone under two heating processes, the heating and cooling then loading process and the simultaneous heating and loading process.The results show that:(1) AE events began to emergein heating process at 50 ℃.The limestone burst into pieces around 320 ℃ along the bedding plane with loud noise, meanwhile AE events increased significantly, characterized as ‘thermo-brittleness' damage.(2) AE increasing stages can be identified during the two loading processes, which is helpful to determination of crack initiation stress and crack damage stress.(3) The strength of limestone decreased with increasing of temperature in the simultaneous heating-loading process.However, thelimestone'ssingle axial compressive strength increased after 300 ℃ temperature treated in heating-cooling process.(4) For limestone in the two heating processes, crack initiation stress and crack damage stress both decreased with increasing of temperature.