A series of rock mechanics tests were carried out on sandstone and granite samples, to study the variation law of rock mechanical characteristics under the coupling effect of freeze-thaw cycling and multiple chemical solutions corrosion. The surface microstructures of rock under different external conditions were observed and compared via intelligent microscopy. The chemical corrosion and freeze-thaw damage mechanism were analyzed. The test results show that the mechanical properties of rock, such as stress-strain relationship, elastic modulus, peak stress and fracture toughness, are less affected by the type of chemical solutions, and are significantly affected by freeze-thaw cycling temperature. The damage degree of sandstone under freeze-thaw cycling is greater than that of granite. The mechanical properties of both rocks decrease with the decrease of freeze-thaw cycling temperature. The relationship between fracture toughness type I and freeze-thaw cycling temperature is quadratic function.