When the ash aquifer into water in mining, in the process of water blocking, the common method was to block the water inrush channel, and the sealing microcracks have higher requirements on grouting materials and grouting methods. In view of this situation, the 90101 working face of Jiexiu Mine and the 2224 working face of Xingdong Mine were taken as examples, the technology of plugging micro-fracture channels was analyzed and studied. According to the actual situation, a reasonable grouting method was selected to ensure the water blocking effect. Practice showed that the selected blocking scheme was scientific and reasonable and achieved the expected results.