Abstract: In this paper, analysis was carried out on the characteristics of the reservoir structure of coal samples taken from six typical mining areas of Pingmei Shenma Group by using the nitrogen adsorption method, with the Langmuir equation, fitting analysis was made on the gas adsorption data, and study was conducted on the influence of the coal pore volume upon the gas adsorption parameters. The experimental results indicated that the process of coal adsorbing gas can be well described by the Langmuir equation; different coal samples had different pore volume and the pore size distribution was non-uniform; the micropores (d< 10 nm) in coal samples were well developed and the gas adsorption mainly concentrated in the micropores; in respect of the control mechanism of gas occurrence, the micropores mainly controlled the Langmuir volume and affected the gas adsorption quantity; the micropores and small pores simultaneously controlled the Langmuir pressure and affected the gas adsorption rate at the stage of low pressure.