Abstract: Aiming at the problem that top coal of open-off cut at large height mining face in a certain coal mine is easily broken and open-off cut is very difficult to support, a scheme of digging out broken top-coal is proposed, that is super large section unconventional open-off cut. Aiming at support problem of open-off cut and combining site actual, the software FLAC^3Dis applied to analyze the deformation range and stress distribution of new open-off cut, the damage depth of the surrounding rock is obtained. This paper puts forward supporting scheme of high strength,high rigidity with wire meshes beam and cable anchor. The field application results show that the scheme is reasonable.