Abstract: In order to scientifically evaluate frozen rock slope stability and keep slope safe with suitable technology in open-pit coal mine, and the changing law of physical and mechanical parameters are analyzed. The results show that the mechanical parameters increase while the rock is frozen, but the rock strength decreases after freezing and thawing cycles. Because rock mass has double properties of material and structure, damage of material and structure of rock mass is significant during freezing and thawing cycles, and freezing and thawing cycles is a key factor of slope stability. Based on the survey of slopes in Juhugeng coal mining area, and due to difference of slope strata, slope presents several stable and failure forms. Uniting generalized H-B failure criteria and strength damage law of rock block and rock structural plane during freezing-thawing cycles, the damage law of rock mass could be calculated, and it is an important theoretic foundation to analyze rock slope stability in freezing and thawing environment.