Abstract: In order to solve high difficult construction of the open- off cut in the steep inclined seam,the personnel up and down movement and the roof falling,personal injured accidents frequently occurred by the flying rocks,based on the open- off cut of No. 3212 fully-mechanized coal mining face in Lyushuidong Mine as a study object,th e open- off cut construction plan was provided with a drilling rig applied to drill a borehole from a bottom to upper seam to form a coal falling channel and then to ream the borehole to the designed cross section from the upper to the bottom. Based on the analysis on the technical difficulties of the construction,technical measures of the boreh ole drilling,reaming,borehole wall protection,jamming protection,cleaning as well as the reaming,support and others of the open- off cut were provided. The industrial test re, sults showed that the borehole drilling method from the bottom to upper in the steep inclined seam with the drilling rig could replace the manual blasting of the small cross section to form the coal falling channel and could effectively eliminate the safety danger to the personnel by the seam falling. Meanwhile,the plan could eliminate the secon dary failure of the surrounding rock in the open- off cut and the deformation value of the surrounding rock was obviously reduced to ensure the safety construction of the op . en-off cut and to ensure the safety production of the mine.