Abstract: To address the unresolved issue of the deterioration evolution of rock relics in the Helan Mountain region induced by soluble salt solutions, this study selects calcite-cemented inequigranular feldspathic sandstone as the research object. Considering the actual climatic and hydrological conditions of the relic area, two salt solutions, NaCl and CaCl₂, are employed to conduct freeze-thaw cycling tests and triaxial compression tests, with a dry control group for comparison. The variations in P-wave velocity, mass, porosity, and rebound value of the specimens are systematically analyzed, and the degradation characteristics of rock strength with increasing freeze-thaw cycles are investigated. Furthermore, taking into account the mass loss rate, a damage variable is defined by combining wave velocity and porosity to enable quantitative evaluation of rock damage. The results indicate that under both chloride salt solutions, the elastic modulus, peak stress, wave velocity, and rebound value decrease as a quadratic function of the number of cycles, whereas porosity and mass loss rate exhibit a quadratic increasing trend. The physico-mechanical indicators of the dry group follow the same trend as those of the salt-solution groups but conform to a linear relationship. After 40 freeze-thaw cycles, the elastic modulus of rocks in chloride salt solutions decreases by approximately 20%, which is about four times that of the dry group, demonstrating that soluble salt solutions significantly accelerate rock deterioration, with the weakly acidic CaCl₂ solution exerting a more pronounced effect. The proposed multi-parameter damage variable effectively overcomes the limitations of a single indicator, and its reliability is validated within a 90% confidence interval. Furthermore, the microscopic mechanism by which the weakly acidic CaCl₂ solution accelerates cement dissolution is elucidated, and an empirical chloride-salt-freeze-thaw coupled damage model is established, enabling a preliminary quantitative grading protection for the relic rock mass.