Abstract: The proposed open-pit mine has a length of 1 670 m, and the mining depth is generally over 300 m, and the highest slope is over 600 m, which is an important project.According to the slope height of different position, slope engineering geological petrofabric distribution characteristics, the rock groups of rock quality grade and slope surface tendency with the advantage of rock mass structure, degree of slope rock mass complete several indexes such as the relationship between the slope is divided into five areas.In order to study the relationship between the stability of the high slope and the excavation slope angle of the large open-pit mine, and the relation between its stability and the groundwater level, this paper that combined with the high and steep slope in the Xiarihamu Ni-Co mining area determine the minimum mining slope angle under the same water level and the highest groundwater level under different mining slope angles for the east end slope of the large open-pit mine on the premise of considering the change of rock mass saturation above the groundwater level.The above results are obtained based on the relationship between slope stability coefficient and groundwater level under different mining slope angles which calculate by finite element software ABAQUS and shear strength reduction method.Finally, the analysis of the results about this study obtains the importance of the mining slope angle and groundwater level to the stability of high and steep slopes, and puts forward a series of suggestions for excavating the eastern end of the large open-pit mine.At the same time, this study is of great significance for the excavation of other areas and surrounding similar projects.