NOVELTY - Method for producing compost and liquefied fertilizer involves storing litter from cattle shed in a storing tank, passing the litter through a drier, drying the litter, cutting the dried litter, mixing liquid organic waste, livestock excretion, dried litter of livestock shed, livestock waste including litter, expanded and softened rice hull, and four kinds of combined microorganism with organic material in fermenting tank, performing aerobic fermentation process in the fermenting tank, and treating the organic waste.    USE - The method is useful for producing compost and liquefied fertilizer.    ADVANTAGE - The method treats large amount of organic waste rapidly without discharge, is simple, environmentally-friendly and cost-effective, produces high quality organic fertilizer, reduces environmental hazards caused by livestock waste and liquid organic waste, and avoids generation of bad odor.    DETAILED DESCRIPTION - Method for producing compost and liquefied fertilizer using water control agent in cylindrical or polygonal encapsulated fermenting tank involves storing litter having length of 300-50 mm and water content of 60-70 wt.% from cattle shed in a storing tank, passing the litter through a drier, where hot air at 90 degrees C is provided before being added to mixing and fermenting tank, drying the litter until the water content reaches 10-15 wt.%, cutting the dried litter to a length of 5 mm to have moisture absorption amount of 20-40 wt.%, mixing liquid organic waste, livestock excretion, dried litter of livestock shed, livestock waste including litter, expanded and softened rice hull, and four kinds of combined microorganism with organic material in a cylindrical or polygonal encapsulated fermenting tank, performing aerobic fermentation process in the cylindrical or polygonal encapsulated fermenting tank, and treating the organic waste. An INDEPENDENT CLAIM is included for device for producing compost and liquefied fertilizer, which comprises air line for aerobic fermentation process, where air is injected and fermentation of the livestock excretion is performed in fixed space, litter reservoir, deodorization tower for removing bad odor generated due to rotting of raw materials, tanks for storing organic matter, and mixing tank.