Abstract: With the gradual development of mining, the underground mining will destroy the original equilibrium state of the slope and to reduce the stability of slope. On the basis of this, a similar simulation test is used to study the deformation and failure of the mining slope under the composite mining. The results show that: in the case of underground mining and excavating, the initial pressure step, the collapse height, the collapse angle in 4^# seam, and the initial pressure step, the collapse height, the collapse angle in 9^# seam accord with actual project condition. With the increase of the mining length of the 4^# seam, the sedimentation of the internal overburden of the slope is also increased under different force; with the continuous increase of the mining length of the 9^# seam, the subsidence and collapse of the slope are also increased.