NOVELTY - An organic waste mixed fermentation biogas processing method involves pretreating organic waste of crop residues, animal manure, rubbish, gardening, food waste or sludge. The solids content of the feedstock slurry pool material is adjusted to 10-12%. The feedstock slurry pool material is stand and hydrolysis acidification reaction is carried out. The hydrolysis acidified material is put into an anaerobic fermentation unit of biogas production. The anaerobic fermentation of bio-gas is put into biogas purification system. The fermentation residue is subjected to solid-liquid separation.    USE - Method for processing organic waste mixed fermentation biogas.    ADVANTAGE - The method enables processing organic waste mixed fermentation biogas with reduced size of the anaerobic fermentation unit, water system and improved performance of fermentation system, thus reducing capital and operating costs of biogas projects.    DETAILED DESCRIPTION - An organic waste mixed fermentation biogas processing method involves pretreating organic waste of crop residues, animal manure, rubbish, gardening, food waste or sludge by crushing crop straw into 10 mm or less and putting the crushed product to a pool. Livestock manure is sent to the pool after desanding. Rubbish is cleaned, crushed to 10 mm or less and sent to the pool. Gardening rubbish is cleaned, crushed to 10 mm or less and sent to the pool. Food waste is cleaned, degreased, crushed to 1 mm or less and sent to the pool and sludge is directly sent to pool. The solids content of the feedstock slurry pool material is adjusted to 10-12%. The feedstock slurry pool material is stand for 12-48 hours and hydrolysis acidification reaction is carried out. The hydrolysis acidified material is put into an anaerobic fermentation unit of biogas production through high concentration of feed pump, at 35-38 degrees C to produce methane gas with a rate of 1.0-1.5 m3/m3.d. The anaerobic fermentation of bio-gas or car carrier gas is put into biogas purification system. The fermentation residue is subjected to solid-liquid separation and biogas is obtained after 2-4 weeks of composting solid organic manure, where the biogas slurry is utilized to regulate the production and processing of liquid organic fertilizer.