Abstract: The distances from 102 coal seam to the confined aquifers of the 5th limestone and the Ordovician limestone were 23.9m and 49.6m.By theoretical analysis,that coal seam floor failure caused by mining 9th coal came through 10606up working face,and increased 23% and 12% to each water inrush coefficient of the confined aquifers,so the threat of water inrush in working face gone up.For the safety of 10606up working face and based on the actual production of mine,we employed the floor grouting to inhance the aquiclude.Combined with grouting diffusion radius and water yield of the 17 grouting drills and mining situation,the thickness of aquiclude increased and zone of aquiclude got inhanced,so the minning safety was guaranteed,and could be used for reference in similar situation.