Abstract: Both the stress environment and the size of underground excavation influence the stability of the mining face and the slope. Numerical analysis of FLAC^3D was used to reveal the stress environment arouiad the excavation in the slope, discuss the strata movement, stress distribution and failure mechanism, and analyze the stability of the slope affected by underground excavation. The results show that local curved failure zones may become worse during underground mining under the disturbed slope, but the stability of the slope as a whole will not be changed. For the unloading effect, the arching mechanism in the roof strata is weakened, and the probability of catastrophic collapse exists in roof strata above the mining zone.