Abstract: Coal reservoirs are often connected to hydrogeological systems through faults, allowing groundwater with mineralization to intrude into coal seams. In order to improve gas extraction, it is necessary to explore the effect of coal with different moisture content and salinity conditions on CH₄ adsorption. By means of various experimental tests, such as XPS, FTIR, we constructed macromolecular structure models of Dongqu 8^# coal with different moisture content and salinity conditions, conducted isothermal adsorption simulation experiments, and analyzed in detail the effects of coal models with different moisture content and salinity conditions on the adsorption capacity of CH₄. The results showed that the adsorption capacity of CH₄ decreased with the increase of moisture content and salinity in coal; the effect of moisture content on CH₄ adsorption was greater than that of salinity on CH₄ adsorption; the ability of sodium salt to affect the adsorption of CH₄ by coal was ranked from largest to smallest as follows: Na₂CO₃ > NaHCO₃> NaCl; electrostatic potential distribution: | Na₂CO₃ electrostatic potential| > | NaHCO₃ of electrostatic potential| > | NaCl of the electrostatic potential|, it can be seen that the electrostatic force affects the strength of adsorption, the greater the value of the electrostatic potential of the ions in the salt, the stronger ability the coal to adsorb CH₄.