Abstract: In order to study the methods of non-equidistant holes arrangement and drainage effect evaluation, a set of principles and methods of non-equidistant holes arrangement were suggested based on aging characteristics of borehole drainage radius. On the basis of the “3σ” criterion in probability theory and mathematical statistics, a “3σ” threshold value used in division evaluation unit was proposed considering the borehole spacing, drainage time and methane content in coal bed. Finally, the methods were used to the X1301 working face of Sihe Coal Mine. The establishment of this method provides an operable method for drainage effect evaluation and non-equidistant holes arrangement.