Taking the working face of bifurcated coal seam mining in Jiulong Mine as the engineering background, the development characteristics of water conduction fracture zone in the process of bifurcated coal seam mining were studied by numerical simulation method. The results showed that when mining the bifurcated coal seam, the development range of the overburden fracture zone was small, showing a small arch shape ; after the coal seam was merged, with the increase of mining height and distance, the development range of fracture zone increased rapidly firstly and then gradually stabilizes, and the final distribution pattern showed a large arch shape. Based on this, the relationship model between the development height of fracture zone and mining distance was constructed by curve fitting. Finally, the height of the fracture zone was calculated by the formula, and the difference between the numerical simulation results and the theoretical calculation was within a reasonable range, which verified the reliability of the numerical simulation results.