Abstract: In order to study the influence of moisture content, particle size, temperature and other factors on the gas adsorption characteristics of coal samples, the coal samples of No.2 coal seam of Huangling No.2 Coal Mine were selected. Through the HCA type high pressure gas adsorption device, the isothermal adsorption experiments of coal gas under different water content, particle size and temperature were carried out by orthogonal experiment method, and the main control factors influencing the performances of gas adsorption were obtained. The results show that the adsorption curves of coal to gas accord with Langmuir theory under different moisture content, particle size and temperature; the sensitivity of each factor to the adsorption constant a value is in the order of particle size > temperature > moisture content, the influence degree of particle size is 3.126 times of water content and 4.458 times of temperature; the sensitivity of each factor to the adsorption constant b value and adsorption saturation X value is in the order of temperature > particle size > moisture content. The influence degree of temperature on adsorption constant b value is 3.946 times of particle size and 7.719 times of moisture content. The influence degree of temperature on adsorption saturation X value is 4.947 times of moisture content and 1.918 times of particle size. The coal preferentially absorbs water, and the gas adsorption capacity decreases with the increase of moisture content. The gas adsorption process is exothermic, and when the temperature increases, the gas adsorption capacity decreases; the particle size decreases, and the specific surface area of the coal sample increases, so the gas adsorption capacity increases.