Abstract: In order to investigate the mechanism of ultrasonic wave on the actual coal seam to increase the permeability and promote the gas diffusion, this paper carried out diffusion kinetic experiments to analyze the effects of ultrasonic power, water content of the coal body and ultrasonic time on the parameters of the gas diffusion of the coal body. The results show that after ultrasonic treatment, the gas adsorption and desorption and diffusion characteristics of coal body are basically unchanged, but the adsorption and desorption amount and diffusion capacity of coal body are significantly changed. 18kW ultrasonic treatment increased the gas desorption of coal body by 18.17%～24.29%. The gas diffusion coefficients of raw coal, dry coal samples and water-saturated coal increased by 12.29%, 8.32% and 17.26%, respectively, after ultrasonic treatment, and the water content of the coal helped to enhance the ultrasonic penetration effect.