U-shaped ventilation was adopted in the fully mechanized coal mining face of the Nianyan Coal Industry. The wind flow at the upper corner was not smooth during the mining process. The diameter of directional long boreholes was used to extract gas in the goaf, and the theoretical layout of the directional boreholes was initially determined through theoretical analysis. Numerical simulation studies showed that the optimal drainage negative pressure was 15 kPa, and the optimal distance between the directional boreholes and the bottom of the coal seam was at a distance of 20 m, the drilling field was arranged in the return air bypass of the 4202 working face for high-level large-diameter directional drilling. During the application, the average concentration of gas extracted during drilling was 18%, and the gas at the upper corner was stable at about 0.4%, with good effect of corner gas treatment and drainage effect.