Abstract: We expound domestic research methods and development process on forecasting coal and gas outburst intensity and analyze the limitations of existing research findings, the concepts of measured index and predicted index on outburst intensity are proposed. The index of initial releasing gas expansion energy can really reflect the essence of outburst intensity from outburst mechanism aspect, and it is the ideal index of outburst intensity prediction. According to expansion energy of initial releasing gas, outburst intensity can be classified into four grades as no outburst, slight outburst, strong outburst, extremely strong outburst with translating the prediction results by classifying into corresponding amount of common explosives.