Abstract: In order to determine the critical value of gas content and predict the coal and gas outburst region, a method to determine the critical value of gas conten t was provided based on the gas adsorption and desorption experiment. With the gas adsorption and desorption experiment, a relation formula between the gas pressur e, gas content and the drilling cuttings desorption index Ah2was established, the critical value of the drilling cuttings desorption index Oh2obtained in No. D6 seam of Pi ngmei No.1 Mine was 160 Pa and the relevant minimum gas content calculated was 5. 04 m3/t when Oh2was in the critical value, which had good agreement with the g as content critical value of 5 m3/t preliminarily determined with Langmuir formula method. The engineering application showed that the method to determine the critical value of gas content based on the gas adsorption and desorption experiment was rational.