Abstract: In order to ensure the safety mining in the steep inclined seam under water body, based on the deposit conditions of the deep inclined seam in South N o.2 Mining Block of Longhu Mine, the dispersed element UDEC2D numerical calculation method was applied to study the goaf roof control method effect of the deep inc lined seam mining to the surrounding rock control of the coal mining face. The results showed that when the goaf was not backfilled, the surrounding rock deformation of the coal mining face would be highest and the immediate roof deformation would be parabolic;when the goaf was partially backilled at the low section with 40 m, the ro of deformation would be linearly increased in tendency and at the no backfilling section of the goaf, the roof deformation would be parabolically increased in tendency.w hen the goaf was fully backfilled under the different backilling strength, the roof displacement would be varied in linear and the elasticity module of the backilled mass would be 0.5 GPa which could meet the requirements of the roof support under the available mining depth;with the backfilled mass strength increased in the partial bac kfilled goaf and the fully backilled goaf, the deformation of the roof and floor would be in a decreasing tendency and the roof control effect of the fully backilled goaf w ould be obviously better than the partial backilled goaf.