The Huainan coalfield is located at the southern edge of the North China, and as a typical North China coalfield, the deep coal seam in Huainan is mined over the limestone karst bearing water of "high water pressure thin water blocking layer", which is threatened by high-pressure limestone karst bearing water, and at the same time, due to its special geographic structural location, various kinds of perpendicular hidden structures exacerbate this threat. This paper focuses on the design and construction of multi-branch horizontal wells through the engineering practice. According to the relevant requirements of the Rules of Coal Mine Water Control, and taking into account the geological and hydrological geological conditions and their peculiarities in the Huainan Coalfield, key process links such as design, multi-branch horizontal well drilling construction, seismic evaluation, exploration, treatment, verification and evaluation, with the aim of formulating a plan for the exploration and advanced treatment of limestone water damage in the area, with reasonable suggestions are made.