Abstract: In order to research the damage characteristics and water-inrush mechanism of mining induceel floor in the deep mine and the difference between in dee p and shallow area, the floor of lower group coal in Huaibei Mining Area was set as study object, and three floor models of different mining depths were established. FL AC3 Dhas been developed on the basis of FISH language and the damage characteristics in mining of floor of different depths under fluid-solid coupling were analyzed and compared comprehensively. The study results showed that the damage form of floor in deep area after mining was quite different from the one in shallow area. In-si tu tensile fracture developed on the roof of aquifer under coupling of high crustal stress and confined water of high pressure in deep area. Progressive intrusion would h appen under the influence of mining, while there was no such phenomenon in the shallow mining. Water inrush disaster could happen while the damage zone caused by mining connected with the progressive zone. The results show the damage characteristics of mining of floor in deep area and the mechanism of water-inrush that can b e concluded as follows: in-situ tensile fracture developed fractures connected with the progressive zone, in-situ progressive zone developing, the damage zone caused by mining connected with the progressive zone.