Abstract: The effect of the stability of thick coal seam upper slice pillar residual " mined out area " on residual coal repeated mining face was studied with numerical simulation. Some conclusions can be drawn as follows. When mining face passed through wider residues goaf, its roof vertical stress presented the law of "weak-strong-weak-strong-weak", and the stress peak before goaf was larger than the stress behind the goaf; the different lithologies of residues goaf floor has less influence on pressure distribution law of repeated mining face roof.