The "borehole in place of roadway" technology has been gradually adopted in coal mine abandoned area gas extraction construction due to its ability to effectively increase the connectivity of fractures in the formation, enlarge the area of gas outflow channels, and improve gas extraction efficiency. According to the requirement of directional drilling of large diameter near horizontal high drilling hole, the helical tooth arrangement principle is adopted to optimize the circumferential layout of the blade. Improve the adaptability of drill bit to near horizontal drilling; Optimize the bit profile to ensure the bit steering performance; Adjust the waterway structure to ensure the drill washing effect; And through the optimization of surface additive technology, the automatic additive process is developed to harden the surface of the drill bit. The newly developed drill bit has been used in the field test of high level drilling in a coal mine in Huainan. The results show that when drilling into the sandstone and silt stone strata in the roof of coal seam, the average life of the two bits reaches 1898.5m. During drilling, the bit can drill along the preset trajectory, the drilling pressure is stable, the drilling pressure is stable, the drilling pressure is stable, the drilling pressure is smooth, and the water hole is not blocked after lifting the drill, which verifies that the tooth layout and water channel design are reasonable. The surface of the bit body has almost no wear, no cracks and no falling off, indicating that the bit additive technology is reasonable, the combination strength of the additive layer and the bit body is good, and the material hardness is high, which meets the requirements of large-diameter directional drilling with hole substitution, and provides a new solution for the design and manufacture of large-diameter directional drilling bits.