In order to understand the influence of different propelling distances on water inrush from the working face floor during the mining of steep inclined coal seam, the authors detected the water-bearing strength and water-bearing position of the working face floor at 31515 of a coal mine in Shandong Province by TEM. Then, the fem difference software FLAC ^3D was used to simulate the formation and evolution of water inrush channels on the bottom of steep inclined coal seam face in the confined aquifer when different propulsion lengths were simulated. And the change of the pressure water conduction height and seepage flow vector of the bottom plate with the advance of the working face was investigated. The results show that the working face stoping makes the floor form the plastic failure zone, and under the action of the pore pressure of the water in the confined aquifer of the floor, the uplift zone of confined water and the mining failure zone of the floor are conductive, thus the risk of water inrush from the coal seam floor is easy to occur.