Abstract: The paper comprehensively analyzes the sealing mechanism of two kinds of sealing technology between the capsular bag grouting and polyurethane.It is found in Xin’an mine site inspection of Yima Group that the gas drainage concentration of capsular bag grouting sealing is significantly higher than the drainage concentration of polyurethane sealing.The drillings average gas drainage concentration of the capsular bag grouting sealing is still 2.23 times of the drillings average gas concentration of the polyurethane sealing after drainaging 3 months.