Abstract: Based on a working face in a coal mine in western Henan, the distribution of floor force and abutment pressure of fully mechanized subsection filling face in steeply inclined coal mine is analyzed.With the help of FLAC^3D finite element difference software, the failure mechanism of fully mechanized subsection filling face floor in steeply inclined mines is studied.The results show that the filling body in goaf can support the direct roof and control the sliding deformation of the floor.With the increase of the excavation depth of the working face, the floor of the fully mechanized mining subsection filling face in steeply inclined mines is most likely to be damaged in the middle and lower part of the floor.The plastic area of the working face concentrates in the middle and lower part of the floor, and with the deepening of the coal seam excavation face, the depth and scope of the plastic area of the floor gradually increases, and the area affected by the coal seam mining gradually deepens.