Mechanical properties of rock at high temperature are of importance for structure design and safety assessment in underground rock engineering. Brazilian disc test, axial compressive test and three-point bending test are adopted to determine the tensile strength σt, uniaxial compressive strength σc, elastic modulus E and Mode I fracture toughness KIC of sandstone at high temperature. Test results show that all of these values (σt, σc, E and KIC) are linearly increased with the increasing temperature below a certain temperature, 200 °C or 250 °C, and decreased above this temperature. The linear equations are σt=0.010 9T+2.322, σc = 0.181 9T+63.138, E=0.004 9T+10.498 and KIC =0.003 1T+0.60, respectively. Mineral compositions and microstructures of natural rock material have great influences on its mechanical properities at high temperature. Dominance of drying or microcracking would lead to the improvement or degradation of mechanical properities of rock.