The gas drainage with boreholes is the most direct and effective means for gas control. According to the principle of directional drilling technology in coal mine underground, an effective drilling technology applicable to medium hard coal seam is put forward to realize effective long directional drilling by combining compound drilling technology and directional drilling technology in coal mine underground. The field test proves that this method can make the borehole wall smooth, prevent pump suffocation and sticking, reduce the accident processing time and improve the successful drilling rate and drilling efficiency. By the application of this technology, average ROP increases by 26.8% compared with the conventional directional drilling.