Provided is a method for producing corn gluten hydrolysate comprising: (a) separating corn gluten protein by removing carbohydrate, water soluble sugars, inorganic materials and fiber material; (b) preparing corn gluten protein lysate by carrying out acid hydrolysis, enzymatic hydrolysis or natural fermentation; and (c) increasing a content of branch chain amino acid (BCAA) which is included in the hydrolysate by isolating, concentrating, precipitating, desalting and filtering the resultant corn gluten protein lysate. With improved pre-treatment and concentration processes as compared with the conventional method, the hydrolysate prepared according to the present invention is rich in amino acids and low-molecular-weight peptides. In particular, free amino acids and branched-chain amino acids (BCAA) are included in large quantity.