Gas drainage in Wangpo Mine with certain defects due to the sealing process of the drilling, resulted in a lot of drilling hole sealing lax, drilling leakage, making the gas drainage efficiency low, and poor gas drainage. In order to solve this problem, based on the drill cutting method, it was determined that the reasonable sealing length was 12.0 m, and the WGC-II type was applied by using Hengda sealing material and radial expansion active pressure type grouting sealing technology. On-site observation of the gas sampling instrument of gas extraction pipeline showed that the sealing effect was greatly improved and the ideal gas drainage effect was obtained.