Food waste from each household include inpurities such as vinyl, shells, irons, sands, etc. The inpurities if not removed adequately, the anaerobic digestion facilities operating isn’t impossible efficiently. In this study, to solve this problem, the discharged food waste is treated by shredder, pulper, drum screen, cyclone, grit chamber and after pre-treatment step 5 it removes more than 97% foreign substances. It has maintain particle size less than 3mm, TS 10% of slurry concentration so it maintain optimum liquefaction of hydrosis, acidogensis. After that methanogensis produce maximimum of the biogas production rate, as well as the stable operation of the digester is possible. Inpurities are removed completely through a multi-stage pretreatment (shredding and screening process). At the same time the particle size is minimized and after digestion of wet mesophilic two-phase anaerobic digestion process the maintains TS concentration of less than 4%. Generation of bio-gas maintain at least over 100㎥ per ton substrate food waste and this technology is optimal economical and efficient.