Abstract: Studying adsorption/desorption character of anthracite on air dry basis in CH₄ isotherm experiments was performed,and the result shown that the desorption hysteresis is obvious and remainder percentage of CH₄ is as high as 56%.To make further study designed the experiment of pyrolysis and activation of coal to increase the specific surface area of coal sample,then researched adsorption/desorption character of coal,carbon and activated carbon in CH₄ isotherm experiments,found that the amount of adsorption is evidently increasing with increase of specific surface area,while remainder percentage is not so markedly change as commonly expected,moisture,one of the most important factors in result,is examined.The result shown that the moisture can obviously affect desorption remainder percentage of activation sample.