Abstract: Aiming at the problem of damage and deterioration of slate on the slopes of open-pit mines in cold regions under freeze-thaw conditions, various types of slate samples from a typical open-pit mine in Inner Mongolia were subjected to laboratory tests, including freeze-thaw cycling, uniaxial compression, and P-wave velocity measurements. The experiment simulated the freeze-thaw process in a natural environment, set different cycle times, and systematically analyzed the influence laws of freeze-thaw action on the physical and mechanical properties such as mass loss, longitudinal wave velocity, and mechanical parameters of rock mass. Based on obtaining the evolution characteristics of the main physical property parameters of the slate, the damage evolution equation considering the influence of the number of freeze-thaw cycles was constructed, and the damage expansion process and failure mode of slate at different freeze-thaw stages were deeply analyzed based on the numerical simulation method. The test results show that with the increase of the number of freeze-thaw cycles, the mass of slate gradually decreases, the propagation speed of longitudinal waves significantly reduces, the uniaxial compressive strength and elastic modulus continuously decay, and the overall trend shows an obvious deterioration. There is a negative exponential attenuation relationship between the elastic modulus and the number of freeze-thaw cycles. After 20 freeze-thaw cycles, the decrease in the elastic modulus exceeds 50%, indicating that the freeze-thaw process has a significant weakening effect on the structural integrity of the rock mass. In terms of microstructure, the initial micro-fractures within the slate gradually expand and connect, the damaged area increases, and the local cracks develop into identifiable macroscopic cracks. With the accumulation of the number of freeze-thaw cycles, the failure mode of rock has changed from the early single through fracture to a complex failure form with multiple non-through fractures coexisting, and the failure paths tend to be dispersed and nonlinear. The numerical simulation results further indicate that freeze-thaw damage not only reduces the overall bearing capacity of the slate, but also promotes the concentrated distribution of the damage area in the middle of the specimen and the joint parts at both ends. The evolution of the damage field is highly consistent with the stress concentration area. This reveals the coupling effect characteristics of freeze-thaw cycles on the strength and structural evolution mechanism of slate.