In order to improve the accuracy of coal and gas outburst prediction, guarantee safe and efficient propulsion of mining face and reduce the cost of outburst prevention, by fully considering the interval attributes and weights of the three indicators (the prediction rate & accuracy rate of coal and gas outburst, and accuracy rate of no coal and gas outburst), we use the method of multilevel incidence decision of multi-attribute interval number to calculate the optimal interval of comprehensive prediction index F ′of Zhangji coal mine, and its value is ［370,380］. According to the method of multi-weighted index gray target decision method, the top-ranking of F′ is 400, 390, 380. The intersection of the optimized interval and the top-ranking of F ′ is 380. Case study results shows the method is reasonable.