Abstract:According to the special conditions of new south airshaft in Tonglushan Mine, a method of grout sealing water outlet in crosscut by throwing grout mixture at shaft collar has been developed to control water flooding in the shaft. The authors calculate and analyze the thickness of subsealing layer, the operation programe of subsealing grout and the quantity of grout. The application of this grout subsealing method has obtained a good result in the project.