In order to ensure the gas drainage effect of the 18308 working face, through the specific analysis of the gas drainage effect and the drilling sealing mechanism under the original sealing technology of the working face, it was proposed to use the thickening expansion slurry sealing technology to seal the hole. The specific conditions of the working face were designed for the sealing process, and the application effects were compared and analyzed. The results showed that the concentration of gas extraction was gradually reduced to 10% when the 18308 working face adopted the original sealing technology. The thickening expansion slurry was used to seal the hole concentration, and the gas drainage concentration was consistently maintained at about 60%, which ensured the gas drainage efficiency.