Abstract: In order to mine a Ji Formation coal resources threatened by the Permo- Carboniferous karst water in No. 11 Mine of Pingdingshan Tian’an Coal Company Limited, in combination with the hydrogeologic condition of the mine karst water, the karst development law and the passed year hydrologic information, the paper had an analysis on the mine water filling condition and the distribution law of the karst cracking zone in No. Ji Formation seam and a determination on a method combined with a shallow depth integrated discharging, a deep depth local discharging and local curtain grouting. With an industrial trial of draining lane and draining hole engineering,local curtain grouting and drainage engineering,and local working face waterproofing engineering, the correctness of the combined method was verified. The trial results showed that with a long term comprehensive water prevention and control, By the end of 2016,the water pressure dropped to 0.1 MPa, the threats of the karst water from the seam floor were eliminated and a safety mining was realized.