Abstract: According to the occurrence characteristics of the 5, 7, 9 and 12 main recoverable coal seams in Qianjiaying mine.Through the analysis of gas pressure, gas content, variation of coal thickness in geological structural, structural characteristics of coal, lithology of roof and floor, applying the fuzzy comprehensive evaluation method to calculate its weight.Preliminary determination of geological structural factor may be the key factor.Uniting gas geology and drilling data, the strong and weak relation of each coal seam can be explained by the geological structure factor.The coincidence of coal and gas outburst is the result of the crustal stress, gas and coal structure.According to the fault depth, fault length, fault bar number, density and fold relation, the geological structural factors are divided into four areas.Analytic hierarchy process(AHP) is used to obtain its weight and quantification of geological structural factor.The comprehensive results show that the geological structure is the key factor of coal and gas outburst.