NOVELTY - A garden waste as cogeneration biogas, organic fertilizer, and cellulose is obtained by crushing collected garden waste, removing dust, processing to obtain crushed garden waste, placing crushed garden waste to cooking tank, adding water and alkaline substance, uniformly mixing, performing hydrolysis at 90-120 degrees C for 2-6 hours to obtain solid-liquid mixture, dehydrating to obtain crude cellulose as solid residue and liquid, concentrating liquid under vacuum at 55-70 degrees C, placing into fermentation tank, adding activated sludge, fermenting at 35-55 degrees C for 15-25 days, collecting, and bleaching.    USE - A garden waste as cogeneration biogas, organic fertilizer, and cellulose.    ADVANTAGE - Process is low-cost and non-toxic, saves energy, and has no pollution, and product has high quality.    DETAILED DESCRIPTION - A garden waste as cogeneration biogas, organic fertilizer, and cellulose is obtained by crushing collected garden waste, removing dust, processing to obtain crushed garden waste, placing crushed garden waste to cooking tank, adding water and alkaline substance, uniformly mixing, performing hydrolysis at 90-120 degrees C for 2-6 hours to obtain solid-liquid mixture, dehydrating to obtain crude cellulose as solid residue and liquid, concentrating liquid under vacuum at 55-70 degrees C until solid content of concentrated liquid is 10-30%, placing into fermentation tank, adding activated sludge, controlling pH to 7, fermenting at 35-55 degrees C for 15-25 days, collecting biogas, concentrating fermentation residue under vacuum at 55-70 degrees C until solid content is 40-50%, performing spray granulation to obtain organic fertilizer, washing crude cellulose for 2-3 times, controlling slurry concentration to 1-3%, pulping, dehydrating until pulp concentration is 10-15%, placing into cooking tank, controlling pH of slurry to 8-10, adding hydrogen peroxide (H2O2) solution, bleaching at 70-90 degrees C for 1-4 hours, cleaning, and squeezing to obtain refined cellulose product in which mass ratio of crushed garden waste, water, and alkaline substance is 1:6-10:0.03-0.1, mass ratio of liquid and sludge is 1:0.2-0.4, and ratio of slurry and H2O2 is 1:0.03-0.05.    DESCRIPTION OF DRAWING(S) - The drawing shows a process flow diagram of obtaining garden waste as cogeneration biogas, organic fertilizer, and cellulose. (Drawing includes non-English language text).