Abstract: The similar material experiment and the numerical simulation calculation were adopted to analyze the slope stability in combining mining of open-pit with underground mining.The failure mode and the law of the rocks displacement are studied when mining in single underground mining and the combining mining of open-pit with underground mining. The effect of the open-pit and underground mining on the post slope mining and the adverse conditions are mastered.Based on this，the failure mode and the failure mechanics of slope mining are analyzed.The simulation result indicates that the designed slope can meet the requirement of slope stability on the whole，but the upper stages need to be reinforced and the lower stages need to be monitored to prevent from landslide. 

Key words: Combination of open-pit and underground mining, Similar material experiment, Numerical simulation, Failure mode