Abstract: Based on the potential water inrush danger of floor serious water-bearing layer at Jiulishan Coal Mine in Jiaozuo, the combined method of geophysical prospecting and drilling is used to explore the specific conditions of floor aquifer; on basis of this situation, floor reconstruction technology is applied to treat the water disaster of river-closure area. The results show that floor water-bearing layer water inrush is the major source of coal mine water gushing, many water channels exist in the floor, the largest inflow amount can reach to 42 m³/min with high destructiveness. We adopt floor grouting reinforcement scheme to treat the river-closure area of floor serious water-bearing layer, and make the floor shifting down 40 meters to let the coal seam free from the threat of water-bearing layer and ensure the safety of mining.