Abstract: To study the gas adsorption-desorption effect on the resistivity of coal, resistivity value changing laws were determined by experiment of continuous adsorption-desorption and volumetric adsorption-desorption of coal samples by using high precision resistance test device. The results show that gas adsorption-desorption has obvious effect on the resistivity of coal, and the same rules were shown in the continuous adsorption - desorption and volumetric adsorption - desorption experiment of coal. In the process of gas adsorption, the resistivity of coal decreases gradually first and then tends to be stable with gas adsorption; in the desorption process of gas; the resistivity of coal is linear relationship with gas content. Different adsorption modes, comparing with the same gas content of the corresponding resistivity, it can be found that the resistivity of the equal volume adsorption experiment is obviously higher than that of the continuous adsorption experiment, and when the equal volume of desorption is over, the resistivity of coal is far from the original figure.