As coal seam mined into the deep, the frequency of water inrush and the water inrush risk gradually increased, in order to study the characteristics of deep mining floor water-irruption, with mining area as the background of Jiulong Mine 15252 working face of Xinghan mining area, with theoretical analysis, numerical simulation and in-situ test are studied, the results showed that the deep mining of coal seam mining damage zone and the base plate confined water conductivity belt were bigger than the shallow mining, and deep mining floor water-irruption was lag; In deep mining, floor confined water had transverse percolation along with the advance of working surface, and the formation of floor water inrush passage was prone to take place at the corner of aquifer, and its water inrush passage is shaped as "inverted 八shape". Transient electromagnetic field detection results were in good agreement with theoretical analysis and numerical simulation results. In the same geological condition, floor water inrush accident is formed in the deep mining, but it was not easy to form floor water inrush accident in the shallow mining condition. The research results can be used for reference for coal mining under the same geological conditions.