Abstract: To systematically study the damage and failure laws of the floor under the conditions of mining under pressure in the working face, based on the theories of porous media, elastoplastic mechanics and seepage mechanics, and using the multi-field coupling mathematical and physical control equations, a numerical simulation analysis was carried out, comprehensively considering the coupling effect of stress and seepage pressure. A three-dimensional finite element model was established to simulate the stress field and damage evolution characteristics of the floor under different advancing distances (20 m to 300 m) and aquifer pressures (1 MPa, 2 MPa and 3 MPa). The results show that during the advancement of the working face, the horizontal stress of the floor continuously accumulates, and the local high-stress area gradually expands and forms a continuous concentrated zone after advancing 100 m. With the deepening of mining, the floor damage evolves from local damage in the shallow part to a through-type damage zone in the depth, and the maximum damage coefficient can reach 0.9. Water pressure has a significant promoting effect on floor damage. Under high pressure conditions, the range and depth of crack propagation increase simultaneously, and the damage morphology evolves from a dispersed type to a "bowl-shaped" and "butterfly-shaped" type. Under the 3 MPa conditions, the floor damage zone can penetrate the aquiclude and connect with the aquifer, significantly reducing the water-blocking performance and forming a potential water-conducting channel.