Abstract:The effects of initial saturation on freeze-thaw damage on red sandstone were studied by physical and mechanical experiments before and after freeze-thaw cycles. The initial saturation of the red sandstone samples was set as 20%， 40%， 60%， 80% and 100%， and the number of freeze-thaw cycles was set as 20. The mass and p-wave velocity were measured， and uniaxial compression tests were conducted of the sample before and after freeze-thaw respectively. The experimental results showed that： （1）After freeze-thaw， the physical properties of red sandstone with different initial saturation have changed with the p-wave velocity decreasing， and the mass loss rate increasing. （2）With the increase of saturation， the uniaxial compressive strength and elastic modulus of the sample tend to decrease after freeze-thaw， but only when the saturation is greater than 60%， the decreasing trend is more obvious. （3）With the increase of saturation， the freeze-thaw coefficient decreases gradually. The study can provide theoretical basis and experimental basis for construction of geotechnical works and monitoring and control of geo-hazards in the cold region.