Abstract: The floor damage zone caused by mining disturbance in the working face is an important cause affecting the seepage and water inrush in the floor, which is closely related to the brittleness characteristics of the floor strata. In order to investigate the influence of brittle floor and ductile floor on seepage and water inrush of underground aquifer, the failure characteristics of two lithologic floor under stress disturbance and seepage and water inrush under stress hydraulic coupling were analyzed by RFPA numerical simulation software. The results show that the maximum damage depth of floor presents a positive correlation trend with the increase of mining distance. With the movement of the working surface, the maximum damage depth of the bottom plate will also move, and the more brittle the ductility of the bottom plate, the greater the damage depth of the bottom plate. At the same time, it is proved that brittle floor is more likely to induce seepage water inrush in the floor. The relationship between the brittleness characteristic of coal seam floor and the depth of damage zone of coal seam floor caused by mining is revealed, which provides a reference for the risk assessment and risk prevention of seepage water inrush in coal seam floor.