Abstract: Mining-induced strata separation grouting is an important key technology to reduce surface subsidence, and its effect directly determines the final settlement reduction effect. The layout of grouting boreholes is the key to the final settlement reduction by grouting. In this paper, the complete set of drilling construction technology of subsidence reduction grouting is studied from four aspects, including process principle, process flow, operation points and quality control measures, and a complete set of grouting drilling construction technology is obtained, which is applied to the subsidence reduction engineering practice of railway bridge in Fangezhuang Mine. The results show that the technology increases the injection amount of fly ash slurry by 236 %, and at the same time, through the observation of surface movement, it can be known that the subsidence reduction rate reaches 60.99 % by using this technology. The drilling construction technology has certain guiding significance for the design and construction of related separated grouting subsidence reduction projects.