In order to determine the sensitive index of coal and gas outburst and its critical value, prevent sensitive indicators of the critical value great or small led to outburst. No. 9 Mine of Pingdingshan Mining Industry was taken as sample, “Three-rate” was applied to do quantitative analysis, drilling hole gas emission velocity q and drilling cuttings volume index S were sensitive index of the mine, the critical value of predicting sensitive indicator was settled. The practice showed that predictive sensitive indicators could effectively solve the problem of outburst index, with great significance for guiding the site safety.