Abstract: Borehole sealing is the problem of restricting gas extraction.The sealing materials have experienced the process from cement mortar,conventional polyurethane to inorganic materials,and the sealing process has evolved from the atmospheric sealing to pressure retaining sealing.PD material is the new development sealing material on the basis of existing materials,which not only has the permeability,density of cement mortar,but also has the expansion of the polyurethane material.The pressure retaining sealing holes technique can help the material permeate to the around cracks in the borehole,and improve the sealing effect on the surrounding cracks.The field experiment found that the PD material had good anti-decay relative to polyurethane material,particularly in the sealing of 15 d after application.The pressure sealing technique relative to conventional technology had ideal extraction effect,and the concentration increased by nearly 70%.