Abstract: Longshou mine in Jinchuan adopted the underhand horizontal hegagon drifts and filling method with the mining mode of double middle broader stopes. FLAC^3D numerical analysis software was used to explore the influence of the drift filling method in Longshou mine to the surface subsidence. Through the displacement monitoring of 11 monitoring points at the excavation surface area，it comes conclusion that the surface deformation not only shows the settlement movement，but also is along with a complex arch deformation. At the same time，some areas in the mine should be monitored closely. This provides a theoretical basis and technical direction to prevent a wide range of deformation and failure of the surface.

Key words: Filling, Ground surface deformation, Longshou mine, FLAC^3D