To investigate the effect of cyclic freeze-thaw on the stability of rock slopes,this study examines a rock slope in a mining area in Northeast China affected by seasonal cyclic freeze-thaw. 4 freeze-thaw temperature gradients (-5 ℃,-10 ℃,-15 ℃,and -20 ℃) and 1,3,5,and 7 freeze-thaw cycles were considered to explore the deterioration pattern of rock mass mechanical properties.The stability of the rock slope was evaluated based on the MSDP criterion.Results indicate that with decreasing freeze-thaw temperature gradients and increasing cyclic freeze-thaw,internal frost shrinkage intensified,leading to a decrease in compressive strength by 2.9 %-20.3 %,tensile strength by 6.1 %-24.8 %,cohesion by 6.5 %-13.7 %,respectively and internal friction angle by 2.2 %-17.3 %. For fixed freeze-thaw temperature gradients,the tensile and compressive mechanical properties of samples decreased significantly with increasing cyclic freeze-thaw,showed a recovery,and then stabilized.The largest reduction in mechanical properties occurred after 3 complete freeze-thaw cycles.Fatigue damage caused the development and propagation of internal cracks,with discontinuous cracks gradually extending and connecting.The crack quantity increases with cyclic freeze-thaw.According to microscopic analysis,the essence of rock mass strength deterioration is fatigue damage induced by cyclic freeze-thaw. Safety factors calculated using the MSDP criterion were lower than those determined by conventional limit equilibrium methods.The lowest safety factor was observed at -20 ℃ after 7 freeze-thaw cycles.Under cyclic freeze-thaw,irreversible structural damage occurs inside the test samples,leading to decreased sliding resistance due to deteriorated test sample strength,ultimately lowering slope safety factors.These findings provide a reference for evaluating rock slope stability under cyclic freeze-thaw.