NOVELTY - Method for preparing bio-organic liquid fertilizer, involves (a) processing the domestic waste, cleaning the domestic waste, and separating organic substance from the domestic waste, (b) mixing discharged waste with separated organic substance to obtain raw material liquid, (c) inoculating microbial strains in raw material liquid, and subjecting the raw material liquid to aerobic fermentation, (d) subjecting the product to hydrolysis and methane reaction under anaerobic condition, and (e) inoculating microbial strain in product, and performing aerobic fermentation.    USE - The method is useful for preparing bio-organic liquid fertilizer (claimed).    ADVANTAGE - The method is performed simply and cost-effectively, consumes less time, recycles domestic waste, and enables conversion of organic waste into harmless and odorless product.    DETAILED DESCRIPTION - Method for preparing bio-organic liquid fertilizer, involves (a) obtaining domestic waste as raw material, and microbial strain as biological source, processing the domestic waste, collecting processed domestic waste in bags, cleaning the domestic waste, and separating organic substance from the domestic waste, (b) mixing 75-80% discharged waste which is obtained after cleaning the domestic waste in the step (a) with 20-25% separated organic substance to obtain raw material liquid, (c) inoculating 1-2 wt.% microbial strains in raw material liquid, mixing and uniformly stirring the raw material liquid comprising inoculated microbial strain, and subjecting the raw material liquid comprising inoculated microbial strain to aerobic fermentation at 20-25 degrees C, where the macromolecular organic substance in the raw material liquid is decomposed by microbial strain, the small organic substance in the raw material liquid is decomposed by action of microbial enzyme, and the chemical oxygen demand (COD) concentration of fermented product is 5000 mg/l, (d) transferring the fermented product to anaerobic fermentation processing system, and subjecting the product to hydrolysis and methane reaction under anaerobic condition to remove most of the organic substance, and (e) transferring the product obtained in the step (d) to an aerobic fermentation processing system, then inoculating 1-2 wt.% microbial strain in the product, and subjecting product to aerobic fermentation.