NOVELTY - Anaerobic digestion of cellulose biomass involves (a1) adding 4-10 wt.% mixed alkali and water to the cellulose biomass, fully mixing, regulating moisture content upto 88-92 wt.%, measuring the pH of the material before preprocessing, sealing and storing at 20-25 degrees C for 10-15 hours, and then discharging to obtain pre-processed material; and (b1) recycling black liquor by separating solid-liquid in pre-processed material, subjecting solid material for anaerobic digestion, recycling alkaline black liquor, adding in new cellulose biomass, uniformly mixing alkali and water, and processing.    USE - For anaerobic digestion of cellulose biomass (claimed).    ADVANTAGE - The method forms a whole set of system which results in stable and continuous pre-processing technology so as to reduce utilization of the alkali, achieve cost saving and improve the biodegradability of cellulose biomass, and also improve anaerobic digestion marsh gas production effect, at the same time, effectively reduce the pre-processing influence on the environment. In order to solve prior art problem, the present method uses the alkali pre-processing technology by replacing sodium hydroxide with low cost calcium hydroxide. Compared with the pre-treated cellulose biomass, the alkali preprocessing provides methane in high yield of 45-210%, average % content of effective component of methane is increased by 18-86%, and cellulose biomass removal rate is improved by 22-58%.    DETAILED DESCRIPTION - Anaerobic digestion of cellulose biomass using combination of alkali preprocessing and black liquor recycling, involves: (a1) adding 4-10 wt.% mixed alkali and water to the cellulose biomass, fully mixing, regulating moisture content upto 88-92 wt.%, measuring the pH of the material before preprocessing, sealing and storing at 20-25 degrees C for 10-15 hours, and then discharging to obtain pre-processed material; and (b1) recycling black liquor. The step of recycling black liquor involves carrying out solid-liquid separation in the pre-processed material, subjecting the solid material for anaerobic digestion, recycling the alkaline papermaking black liquor, adding in new cellulose biomass, and uniformly mixing alkali and water, adjusting pH of the material before pre-processing material, adjusting the water content upto 88-92 wt.%, sealing to preserve at lower temperature and then discharging; performing solid-liquid separation to continuously discharge black liquor from recovery boilers; and recycling black liquor for 5-10 times to obtain base connection balance point of the reprocessing cellulose biomass, where the balance point of the mixed alkali amount is a fixed value, after uniformly mixing the material pH value is the step (a1) pre-processing before the pH value of material, then continuously recycling black liquor, is added to the balance point determined as a base, the other condition is not changed to form a whole set of system, stable and continuous alkali combination pre-processing, black liquor recycling biomass anaerobic digestion process.