Abstract: In order to solve the problem of water disaster control of floor in the high-confined water area in working face with large mining length in Chensilou Coal Mine, the technology of floor grouting transformation was adopted in the typical 2517 working face with large mining length of the mine to liberate the coal seams threatened by the limestone water in the Taiyuan Formation of the floor.Through data investigation and data calculation, the reconstruction horizon was selected and the borehole design was carried out.Based on the data of water yield and grouting volume of the floor grouting reconstruction borehole, the water abundance, grouting volume, main injectable fissures, grouting material consumption of different levels of water filled fissures, and the average slurry consumption of a single hole were compared and analyzed.The results show that the water-rich area of the aquifer is mainly affected by fractures, faults, folds and other structures.Aquifers of L ₁₀ limestone and L ₈ limestone are characterized by highly water-rich, uniform distribution and good connectivity.Their aquifers are mainly medium and small scale and large-scale fractures and dominated by small and medium scale fractures.The average slurry consumption in single hole of the working face is about 3.4 times of the water yield in water-filled fissure.According to the results of three times of geophysical exploration, the grouting transformation effect of the floor is remarkable, which basically solves the problem of gushing water of the floor in high-confined water working face in Chensilou Coal Mine, and can provide reference for the treatment of mine water disasters in other mining areas.