Abstract: In order to explore the potential of methanogenic bacteria in Longquan coalbed methane field to degrade methane production in bituminous coal,the enrichment and domestication of methanogens in Longquan coalbed methane field was studied.The laboratory study as well as pilot study on the degradation of coal gas production by methanogens was carried out with Longquan mine bituminous coal as parent material.The results showed that the concentration of methanogenic degradation of bituminous coal increased from 8.2% to 19% after enrichment and domestication of methanogens,the cycle of gas production stability was shortened.In the pilot test,the methanogenic concentration was up to 27.06%,and methane production rate was 0.159 mL/(g·d).By supplementing yeast powder,nitrogen sources,phosphates,magnesium salts,vitamins,and trace elements during the stage of gas recession,the activity of the methanogenic flora could be reactivated and methanogenesis concentration could be increased.The results show that enrichment and domestication of methanogenic bacteria in Longquan coal seam can significantly improve its ability to degrade bituminous coal to produce methane; supplementing nutrients during the decline of fermentation gas production can activate methanogenic bacteria and restore its ability to degrade bituminous coal to produce methane.In the recession period of pilot fermentation gas production,yeast powder,nitrogen source and phosphorus salt were added to the fermenter.Magnesium salts,vitamins and trace elements can reactivate the activity of the methanogenic flora and make it reduce the concentration of methane produced by bituminous coal.