It’s proved for the first time that external solution can promote gas desorption by using independently designed gas desorption measuring device. Two reasons of competed adsorption location between liquid and gas and capillary static driver are analyzed. The result shows that the gas desorption efficiency increases as the concentration of penetrant solution increases and the promotion effect of penetrant solution only occurs in a period of time. Then specific measurements of improving gas desorption efficiency on coal face are proposed. The study can provide reference for solving the time constraint between gas extraction and mining on coal face.