Abstract: In order to improve the control effect of the upper corner and the return air gas of the coal face, large diameter directional borehole is constructed in the coal seam overlying roof slate layer. According to the geological characteristics and mining conditions of roof overburden in working face of Sihe coal mine, and based on the empirical formula, the high-level directional long borehole arrangement layer of roof is determined. Aiming at the problems of low efficiency about pilot directional drilling and graded reaming in the construction of large diameter directional borehole in roof hard rock, the impact screw motor, torsional impactor and two-stage and two-speed reaming drilling tools are respectively applied to pilot borehole construction and reaming construction which can improve the entirety construction efficiency of roof high large diameter directional drilling. The application results in Sihe coal mine show that the drilling efficiency of impact screw motor and graded reaming technology was improved significantly. The maximum drilling rates were respectively 13.6m/h and 11.1m/h. The large diameter and high-level directional long drill hole of Ф 200mm can ensure the effective extension in the seam roof fracture zone and realize the continuous and stable extraction of mining pressure relief gas, which has been obtained good gas extraction and control results, the average gas drainage flow of a single hole can reach more than 3.36m3/min and the instantaneous maximum gas extraction capacity of a single hole can reach 26.0m3/min.