Abstract: In order to further determine the effect of mining height on working face under goaf, avoid upper and lower mined-out areas running through as far as possible, this paper adopted the method of numerical simulation to research abscission layer of overburden stratum, dynamic pressure characteristics as well as the "three zones" fracture height. Simulation results show that: with the increasing of coal seam working face mining height, the tensile failure unit in roof strata above the working face is gradually increase, the increase of mining height exacerbated the hard roof caving and rupture, also reduced the roof fracture interval. With the increasing of mining height, the displacement sinking value during the first weighting is increasing, especially the scaling up of height continuously increasing, which illustrates that coal seam working face under the increase of mining height will promote "three zones" development .