Abstract: At present, the method of using four single indexes to indentify the risk of coal and gas outburst in coal seam is widely used in China,the critical values of outburst risk of the indexes are provided. Only when the measured values of the four single indexes all meet or exceeds the critical value, the seam can be identified as an outburst risk coal seam. This provision ignores the different roles of the different indicators parameters in the outburst.Coal Mine Gas Grade Identification Interim Measures,promulgated in 2011, supplements outburst identification criterion of different gas pressures and strong coefficients, but which ignores the role of two indexes of △p and destruction type of coal. The index weight value method supplements the deficiencies of the existing identification methods, and makes identification result more logical and practical.