Abstract: According to the problems of hardly certaining effective gas drainage radius and having disunity criteria indexes in present site,in combination with the relat ed requirements of available regulations and standards in China,the paper provided a new index of the effective gas drainage radius criteria--critical residual gas pressure. A calculation method of critical residual gas pressure was established. In combination with the mathematical model on radial gas pressure distribution in gas drainage bore hole,a rapid solution method of effective gas drainage radius was designed based on the COMSOL Multiphysics. The solution method was applied to calculate effective gas drainage radius of No. 3 seam in Yuwu Mine of different gas drainage time. With the site measurement,an verification was conducted on the effective gas drainage radius measured in the site and numerical calculation results. The results showed that the new criteria index and numerical solution method of the effective gas drainage radius e stablished were reliable ,and the method could be applied to accurately and rapidly calculate effective gas drainage radius of seam in the target region to provide basis to th e layout of mine gas drainage project,and the mine gas drainage target and safety production were ensured.