Abstract: This paper introduced the commonly used effective drainage radius methods、principles and operation steps. In "three soft" and low permeability outburst coal seam, respectively, with two kinds of methods of measurement of effective drainage radius. Through the comparative analysis, then obtained two kinds of measurement methods in" three soft" low permeability outburst coal seam in the use of the advantages and disadvantages, and ultimately determine a more reasonable method of easurement of drainage radius in the coal seam.