Abstract: Based on the analysis of large outburst accidents from 2000 to 2019, laboratory tests on a large number of basic gas parameters, and previous research results, the method, basis, judgment rule, index critical value and other related problems of outburst coal seam classification were deeply discussed. The outburst coal seams were divided into "general outburst coal seam" and "serious outburst coal seam". On the basis of the classification method of outburst coal seam based on outburst intensity, the judgment rule of serious outburst coal seam was established and the critical value of judgment index was determined. The research results can provide an important basis for the determination of mining procedures, outburst prevention planning and mining replacement planning of outburst mine.