Abstract: In order to study the change of sandstone mechanical properties and the law of damage and deterioration under the action of hydrochemistry-freeze-thaw cycles,sandstone samples with different damage degrees were obtained by immersion in hydrochemical solution and freeze-thaw cycles,and then uniaxial compression experiments were carried out to discuss their mechanical properties,the damage and deterioration mechanism of sandstone was analyzed from a microscopic point of view by scanning electron microscope. The study results show that:① With the increase of freeze-thaw cycles,the longitudinal wave velocity attenuation and mass loss rate of sandstone in acidic solution are greater than those in neutral solution,and the lower the pH value of acidic solution is,the greater the response range is. ② The peak stress is negatively correlated with the number of freeze-thaw cycles,and positively correlated with the pH value of soaking solution. The sandstone presents a tendency of transformation from brittleness to ductility. ③ From the perspective of microscopic structure analysis,it is concluded that the damage and deterioration of sandstone is alternately and continuously accumulated. ④ The elastic modulus was used to define the damage variable of sandstone,and the law function model of the damage variable was established by fitting,which showed that the lower the pH value of soaking solution,the higher the number of freeze-thaw cycles,the greater the damage deterioration degree of sandstone. The study results can provide references for engineering construction in cold areas and underground mining in the acid-eroded environment.