Abstract: According to the theory of fluid mechanics of pipe flow and the principle of gas leakage detection, a quality inspection and judgment method for sealing hole in gas drainage was proposed.That was, by detecting the negative pressure and gas concentration at different depths of the drainage hole in the normal pumping and mining state, the variation of gas drainage concentration with the depth of hole was analyzed. It can quickly and accurately determine the seal quality and air leakage position of the extraction hole. Taking Duanshi Coal Mine as an example, the field test of sealing quality and reasonable sealing depth of drilling holes was carried out by using the quality inspection and judgment method of drilling and sealing.The results showed that when the range of drilling depth is from 9 m to 15 m, the gas concentration varies greatly and exists gas leakage, the sealing quality of the drainage hole is poor and the sealing depth of the hole is insufficient.This method can effectively detect the quality of drilling and sealing of gas drainage. It provides a scientific basis for the adjustment of sealing parameters and the improvement of sealing method in Duanshi Coal Mine.