Abstract: In order to study the gas desorption law of coal in very complex and special conditions of geological exploration, the characteristics of gas desorption in coal in the geological exploration environment are simulated by experimental device. The laws and characteristics of gas desorption of coal samples are studied from the combination of mud pressure, coal sample size, gas pressure and speed of drilling. The key factors that influence the gas desorption in geological exploration were obtained by experiment, and the experimental results provide the necessary basis for the study of gas desorption law in geological survey period.