Abstract: The influencing factors of sealing effect were reviewed, the stress around borehole and the initiative support sealing technology were analysed based on fluid-solid coupling leakage channel model of hole drilled along seam. The results showed: drilling went through “three zones” of in front of roadway, fracture further developed in stress concentration zone; the effect of two disturbances decreased with increase of distance from borehole wall, the superimposed effect of relaxation zone of borehole and roadway appeared local area around borehole, and here the leakage channel formed; without support force, the drainage negative pressure communicated atmosphere easily with in a short time through fracture of borehole and roadway pressure relief, and leakage channel was established; the coal around borehole was reinforced, the relief fracture was healed, leakage channel decreased and the effective drainage time increased with support force, and the effect was more obvious with increase of support force. Further, the initiative support sealing technology was tested, and the results showed: daily average drainage concentration and daily average drainage purity of single hole was nearly 3 times and 1.6 times higher than ordinary capsular bag sealing, and theoretical analysis results were verified.