Abstract: In order to find out the gas desorption laws of loading coal, we designed loading coal and rock constant pressure gas adsorption desorption experiment device, carried out different axial pressure and gas pressure under the condition of columnar coal sample gas desorption experiments, analyzed the influence of axial pressure and gas pressure on the gas desorption, and according to the experience formula of gas desorption, the experimental results were fitted. The results of the study show that: in the same axial pressure conditions, the gas pressure is higher, coal gas desorption quantity is bigger, the desorption rate is faster; in the same gas pressure, axial pressure is higher, the gas desorption amount of coal samples is larger, the rate of desorption is the faster; the gas desorption law of coal sample in axial direction is in accordance with the formula of m, which can be used to characterize the degree of pore fissure's development in the coal body. With the increase of axial pressure, the micro fracture is gradually developed, and the m value is gradually reduced.