In view of the problem of water inrush in the 28 m ash aquifer in the main shaft excavation process of Rongkang Mine, the pre-grouting and water blocking technology was adopted, and the grouting from the top to the bottom, the slurry was gradually thicker and thicker. It was transformed step by step to fill the fractures of the rock formation and form a grouting water blocking layer. The test results showed that the effect of grouting and water blocking was good. When the main shaft was drilled through the aquifer, the water inflow was 4.3 m3/h, and the amount of water inflow was not large, which could ensure the safety of the shaft mining.