Moduli of the four stages during the compression of sandstone after high temperature varying from 25℃ to 1 000℃ are defined

through which the complete stress-strain curves of sandstone are analyzed. The modulus characteristics are analyzed as well as the ultrasonic properties. The damage of sandstone after different high temperatures is analyzed based on the damage factor which is defined by the modulus of compact stage. The research shows that the compression of sandstone after different high temperatures is of prominent staged characteristic. The changing rules of moduli of the four stages with variations of temperatures are not different

among which the modulus of compact stage has a strong relativity with the longitudinal wave velocity. The damage factor defined by wave velocity loses sight of the density and Poisson’s ratio. Avoiding the defect of Vp-method

the damage factor defined by modulus of compact stage is of greater scientificalness. Within the temperature range of 25 ℃-200 ℃

the thermal damage of sandstone is more sensitive to temperature. The results have some guiding significance to rock engineering in high temperature environment.