Abstract: Underground coal mining causes deformation, movement, breakage, and collapse of the overlying rock layers, forming preferential pathways for water migration, which can easily trigger water inrush accidents from the roof, severely threatening the safe and efficient mining of coal. Therefore, accurately determining the height of the water-conducting fissure zone induced by coal seam mining is key to conducting water under coal mining, which helps in targeted prevention and control of mine water hazards. Using a deeply buried coal seam mine as the engineering background, the empirical range for the development height of the water-conducting fissure zone is defined through theoretical analysis. An UDEC numerical model is constructed to analyze the migration characteristics of the overlying rock structure and to preliminarily determine the development height of the water-conducting fissure zone. Pre-mining and post-mining boreholes are designed and implemented, and a comprehensive analysis is carried out using fiber optic monitoring, core characteristics, and borehole TV to further determine the migration characteristics of the overlying rock and the development height of the water-conducting fissure zone. The research results show that: Based on theoretical analysis using empirical formulas, the collapse zone height is 7.71±2.2 m, the fracture zone height is 48.32±8.9 m, and the water-conducting fracture zone height is 44.93～67.13 m, with a fracture-to-mining ratio ranging from 19.53 to 29.19. Numerical simulation analysis shows that as the excavation range of the working face increases, both the range and height of overlying rock movement increase, with the collapse zone developing to a height of 9.1 m. The development shape of the water-conducting fracture zone transitions from an arch to a saddle shape, with the maximum development height reaching 58 m and a fracture-to-mining ratio of 25.22. Fiber optic monitoring analysis shows that at a depth of 253 m from the surface, significant deformation occurs in the rock layers, indicating the main critical layer, with fractures developing within a 32 m range from the coal seam, forming a potential water-conducting fracture channel. Based on the analysis of rock layer characteristics and borehole TV data, it is concluded that the upper limit of the development of the water-conducting fracture zone is at a depth of 537.48 m, with the development height of the water-conducting fracture zone reaching 54.088 m and a fracture-to-mining ratio of 23.51. The comprehensive analysis is primarily based on measured data, with its rationality validated through theoretical and numerical simulations. The final development height of the water-conducting fracture zone is determined to be 54.088 m, with a fracture-to-mining ratio of 23.51. The research findings provide important data support and theoretical basis for ensuring safe production and water hazard prevention in mining operations.