Abstract: In view of the actual occurrence of coal seam, the stress distribution of coal-rock roadway was quantitatively characterized by numerical method. The above simulation results were verified by field investigation. At the same time, the range of "three zones" on two sides of roadway was delimited by using the variation law of punch quantity index per unit length of borehole at different depths, so as to determine the reasonable sealing depth of drillings along the coal seam. The sealing performance of borehole at different sealing depths was characterized by the change of gas concentration and gas purity over time. Combined with the basic principles of economic and scientific extraction, the optimal sealing length was shown. Combined with the distribution characteristics of abnormal stress and failure mode of surrounding rock, a method of fixed-point and fixed-length sealing for low permeability zone of surrounding rock was proposed to improve the sealing performance of borehole. Field experiments show that this method is a feasible technology to realize efficient gas extraction of coal seam and has positive effects on realizing safe, economical and efficient coal seam gas extraction.