Abstract: In order to solve the hidden danger of roof management brought by overlying coal pillars to the underlying coal seam when the coal seam group is mining downward, taking the working faces 43202 and 43203 of Yujialiang Coal Mine as the engineering background, this paper proposes to use the technology of directional long hole subsection hydraulic fracturing to weaken the roof of the working face, and expounds the basic principle of long hole subsection hydraulic fracturing and the layout principle of fracturing holes according to the formula, the fracturing horizon is optimized and the layout of the fracturing borehole and the fracturing parameters are designed. The fracturing results are investigated by using the fracturing curve and the observation data of the ground pressure of the working face after fracturing. The results show that the drilling fracturing breakthrough point is obvious, and the pressure step distance of the working face is small, which achieves the expected pressure relief effect.