Abstract: In order to improve the sealing effect of gas drainage holes, aiming at the characteristics that coal cracks around the borehole are affected by mining and change dynamically, we develop a dynamic sealing technology of drilling holes for gas pre-drainaging. A new kind of flexible gel material with good permeability and self-adaption drilling deformation was used to seal holes. In addition, the repeated grouting material was conducted according to the variation of gas concentration. As a consequence, the dynamic sealing was achieved. Then, the technology was applied to the 13031 working face, Ⅵ_15-17 coal seam of No.13 coal mine of Pingdingshan Coal Co.,Ltd. The results show that the average concentration of gas extraction increases by 2.9 times, from 10% to 39%, and the average pure amount of single-hole gas drainage is 0.075 m³/min, 150% higher than before. The effective period of gas drainage is extended significantly. Therefore, the technology can solve the problem of sealing by conventional materials and technology, effectively enhance the rate of gas extraction and drilling utilization of gassy coal seam and control the gas concentration of mining space.