Aiming at the problems of unreasonable sealing process, short design slurry injection length, low proportion of back slurry, slurry leakage, unreasonable slurry proportion, in the original Anter hole sealing process, the parameters of hole sealing process were optimized respectively from reasonable sealing length of designed borehole, changing the length of "two plugs", adjusting slurry water-cement ratio, etc., and at the same time, the hole-clearing process was increased. The optimized sealing process, such as increasing the time interval between "two blocking" and "one injection" processes, and finally through the test results investigation, the results showed that the optimized sealing process had higher slurry return rate, good sealing effect, and the average concentration of gas in the borehole after 75 d sealing and pumping. It was maintained at 51.63%, which was 18.96% higher than the original sealing process, and the improvement ratio was 58.1%.