Abstract: In order to study the variation law of peak load and fracture toughness of sandstone under different low-temperature conditions, five groups of dry sandstone specimens treated at low temperature and normal-temperature specimens were tested by three-point bending fracture test of half disk. The results show that low temperature has an obvious influence on the peak strength and fracture toughness of different fracture modes. The peak strength and fracture toughness of pure mode-Ⅱ specimens from 20 ℃ to -60 ℃ gradually increase with the decrease of temperature, and slightly decrease at -80 ℃; the peak strength and fracture toughness of pure mode-Ⅰ and mixed fracture mode(Ⅰ+Ⅱ) increase with the decrease of temperature from 20 ℃ to -20 ℃ and decrease with the decrease of temperature from -20 ℃ to -60 ℃. Under different temperatures, the peak strength of pure mode-Ⅰ fracture mode is the lowest, and the fracture toughness K_ⅠC is the highest; the peak strength and equivalent fracture toughness K_eff of mixed fracture mode (Ⅰ+Ⅱ) are in the middle; the pure mode-Ⅱ fracture mode of sandstone specimens has the highest peak strength and the lowest fracture toughness K_ⅡC, K_ⅠC and K_eff changed in a wider range are affected by low temperatures, and K_ⅡC is less affected by low temperatures.