In order to effectively improve the gas drainage effect of the No. 9 coal seam more than 1 000 m drill field, the influence of drilling depth and suction negative pressure on the gas pressure of the drilling hole was simulated by numerical simulation method, and the existing extraction drilling gas was analyzed. The variation of concentration and pure gas flow with extraction time was optimized based on the above analysis results for the mining scheme of No. 9 coal seam. The results showed that the suction negative pressure was increased to 15 kPa, and the total depth of the drill hole in the No. 1 drill field was about 600 m, and drainage about 500 d. The total depth of the borehole in the No. 2 drill field was about 700 m, and the drainage about 600 d. The technology could effectively improve gas drainage efficiency.