Abstract：Based on the uniaxial compression test，the mechanical properties of tuff，granite and breccia after different high temperatures are studied. The scope of this research includes(1) the variation of peak stress，peak strain and elastic modulus with temperature，and (2) the relationship between longitudinal wave velocity and peak stress and peak strain. The temperature varies in the range of 20 ℃，200 ℃，400 ℃，600 ℃，800 ℃，and the heating velocity is 30 ℃/min. The results show that the peak stress and elastic modulus decrease with temperature. The higher the temperature is，the larger the decrement of the peak stress and elastic modulus are. For tuff and granite，the peak strain increases with temperature. However，for breccia，it seems that the peak strain decreases with temperature. Furthermore，the relationship among longitudinal wave velocity，peak stress and peak strain present different laws according to the types of rocks.
