NOVELTY - Preparing methane by increasing biomass raw material anaerobic digestion comprises cutting biomass raw material dry matter into small sections, taking an inoculum, adding the dry matter and inoculum in an anaerobic digester, adjusting carbon/nitrogen ratio, adding hemin or vitamin K2, filling water into the complete anaerobic digester, adjusting initial pH, closing anaerobic digestion, controlling reaction temperature, fermenting by shaking and stirring uniformly, producing methane within 24-36 hours, calculating average daily gas production, feeding or inoculating.    USE - The method is useful for preparing methane by increasing biomass raw material anaerobic digestion (claimed).    ADVANTAGE - The method: reduces power level of the complete system; promotes anaerobic digestion process; promotes growth and activity of methanogenic bacteria; increases efficiency of the hydrolysis reaction system; shortens the anaerobic digestion time; increases methane production yield and conversion rate of poor biomass raw material; and is simple and economical.    DETAILED DESCRIPTION - Preparing methane by increasing biomass raw material anaerobic digestion comprises (i) cutting biomass raw material dry matter into small sections of 1-5 cm; (ii) taking an inoculum; (iii) adding the dry matter and inoculum in an anaerobic digester, adjusting carbon/nitrogen ratio, adding hemin or vitamin K2, finally filling water into the complete anaerobic digester, where the amount of the all materials is 80% of container, adjusting initial pH, where the content of the biomass raw material dry matter is 6-10% of the 80% materials, and the amount of inoculum is 60% of the 80% materials; and (iv) closing anaerobic digestion, controlling temperature of the reaction to 35 plus minus 2 degrees C, fermenting the material by shaking and stirring uniformly, producing methane within 24-36 hours, calculating average daily gas production, finishing the reaction when the daily gas production is less than 25% of the average daily gas production during fermentation process, feeding or inoculating.