Abstract：With the depletion of shallow mineral resources, many open pits have been already or shall soon be switched to underground mining. The safety design of open pit stoppage combined with the opening of underground mine involves many problems. In this paper, FLAC3D is used to systematically analyze the rock layer movement and deformation. Surface displacements of ore-bodies II and IV at different mining levels are discussed. With the determination of parameters of rock layer movements, the open pit slope stability of Yongping copper mine is analyzed. The corresponding movement characteristics of rock mass, maximal vertical and horizontal displacements as well as rock movement angles are obtained. Results show that the influence of ore-body II on the rock layer movement is far greater than that of ore-body IV. The maximum vertical and horizontal displacements all occur in the rock mass located on the eastern slope of ore-body II. The reasonable mining sequence should be ore-body IV first and ore-body II second. A part of the model area is in the state of breakage and limit stability. However, the open pit slope is in an integral stability state as the mining advances. It is shown that the filling method used in the next stage in the mine is feasible. The rock layer movement during the open pit stoppage combined with the opening of the underground mine, simulated by using FLAC3D, gives a true picture of the stress and displacement states of the rock mass.