Abstract: Fushun East Open-pit Mine overlaps with its lower Laohutai Mine and Laolongfeng Mine in space, and is distinguished in elevation, and there is a period of combined open-pit and underground mining in time. On the basis of field investigation, through numerical simulation, the deformation and stress characteristics of the slope under the combined open-pit and underground mining are analyzed. The deformation characteristics of the E8800 and E5400 southern and northern sides are summarized, and the stability of the southern part of the two profiles has been studied. The results show that the plastic zone of the slope rock mass and underground rock mass is basically caused by underground mining at this stage, and only a small area of tensile plastic zone is formed in the southern and northern gangs under the action of open mining. At this stage, the slope of the northern part of the two profiles is not more than 10 degrees, but the plastic zone of the northern part is very developed. In the case of continuous open mining, the stability of the northern part should be paid attention to.