NOVELTY - Tilapia residual waste is ground into minced fillet, the minced fillet is mixed with bran, Aspergillus oryzae spore suspension with inoculated in every 100 g culture medium, cooled, and solid fermentated, to obtain culture medium full of Aspergillus oryzae. The obtained product is ground, added to protein wastewater, stirred, filtered, concentrated, or enzymatic processed tilapia residual waste is added to the filtrate, crushed, specified amount of calcium and magnesium is added with total concentration of 30 g/L, and drum packed, to obtain amino acid liquid fertilizer.    USE - Production of amino acid liquid fertilizer (claimed).    ADVANTAGE - The environmentally-friendly amino acid liquid fertilizer is prepared.    DETAILED DESCRIPTION - Tilapia residual waste is ground into minced fillet by a grinder, the minced fillet is mixed with bran in weight ratio of 3:1, the mixed material is heated by steam at 120-130 degrees C for 14-16 hours, and cooled to room temperature, to prepare solid culture medium. The culture medium is sterilized at 120-130 degrees C for 15 minutes, 1 ml Aspergillus oryzae spore suspension with concentration of 1x 108/ml is inoculated in every 100 g culture medium, cooled, and solid fermentated at 36-38 degrees C for 47-49 hours, to obtain culture medium full of Aspergillus oryzae. The obtained product is ground, 100 g ground yeast is added into 200-300 ml protein wastewater, stirred by stirrer with rotation speed of 60-60 rpm at 60-65 degrees C for 5-6 hours, heated to 1000 degrees C, temperature is maintained for 5-6 minutes, and filtered. The 300-350 ml filtrate is concentrated to 200-250 ml in vacuum, the concentration of amino acid content of more than 100 g/L is detected based on NY1429-2010, if the concentration of filtrate is less than 100 g/L then the concentrating ratio is increased, or specified amount of enzymatic processed tilapia residual waste is added to the filtrate, crushed, specified amount of calcium and magnesium based on NY1429-2010 is added with total concentration of 30 g/L, and drum packed, to obtain amino acid liquid fertilizer.