Abstract: The coal seam in Fengyang Coal Mine belongs to "three-soft" and dip angle coal seam, and thickness is generally in more than 5 m, open-off cut supporting can not adopt conventional "cable anchor" support, open-off cut brush expansion construction process is more complicated. For changing directly blasting mining into fully mechanized mining in Fengyang Coal Mine, how to ensure the safety of fully mechanized mining face open-off cut expansion of brush and supporting process, has become the focus of the work of the mine safety management. Combined with the actual mine production conditions, we propose reasonable open-off cut expansion of brush construction process, and take corresponding safety technical measures, which finally realizes the safe construction of Fengyang Coal Mine "three soft" inclined thick coal seam fully mechanized cut.