Abstract: In order to improve the gas drainage effect of the high gassy and low permeability seam,based on the borehole reaming and completion technology of the C oalbed methane an enhanced gas drainage technology of the borehole was provided based on the mechanical reaming method. The four linkage mechanism principle was applied to research and develop a set of the special mechanical borehole reaming equipment for the gas drainage borehole in underground mine. Based on No. I 1013 co al mining face in Luling Mine as a case,the equipment was applied to construct four groups of the borehole reaming and a continuous monitoring and statistic analysis was conducted on the gas drainage parameters. The experiment results showed that with the application of the mechanical equipment,a reaming diameter of 600 mm would be formed in the gas drainage borehole and the mechanical reaming technology could obviously improve the gas drainage effect of the borehole. In comparison with the conve ntional gas drainage boreholes in the same location,the single borehole gas drainage concentration of the reamed borehole could be improved by 2.73 ~ 3. 39 times and t he pure gas flow was improved by 2.63~ 5. 11 times.