In order to determine the sensitive index and critical value of outburst prediction in 9 and 14 coal seams of Longhua Coal Mine, and to solve the problems of large amount of outburst prevention work and low tunneling efficiency caused by the current index with reference to the recommended values of the detailed rules, the gas desorption law of coal samples and the determination of drilling cuttings desorption index under different pressures were carried out by combining laboratory test with theoretical analysis. The results show that the initial desorption rate of coal samples is fast, and the desorption amount in the first minute accounts for 13% ~ 16% of the total desorption amount in 120 minutes. The average relative error between the desorption amount at 1 min calculated by K1 value and the actual desorption amount was 2.60% - 4.60%, while the error of desorption amount at 4 - 5 min calculated by Δh2 value was 94.73% - 109.95%. The reliability of K1 value was significantly better than that of Δh2 value. According to this, the sensitive index is K1 value. Combined with the critical value of regional gas pressure 0.74 MPa and safety margin, it is recommended that the critical value of K1 of dry coal sample in 9 coal seam is 0.49 mL/(g·min0.5), and that of wet coal sample is 0.38 mL/(g·min0.5). The dry coal sample of 14 coal seam is 0.50 mL/(g·min0.5), and the wet coal sample is 0.38 mL/(g·min0.5). The research results can provide reference for local prediction of similar mines.