Directed hydrolysis of corn crude peptides was performed by sequential digestion with alpha-chymotrypsin and carboxypeptidase A. With the additional step of adsorption of aromatic amino acids by activated carbon, corn oligopeptides with a Fischer's ratio of 41.87 and low bitterness were prepared. The fraction with molecular weight of 180-1000 Da was found to constitute 71.37% of these oligopeptides, where the proportion of Phe and Tyr among all amino acid residues was only 0.73%. In addition, a model of liver injury induced by carbon tetrachloride was established. Through the analysis of the body mass index, liver index, liver histopathological features, and various serum biochemical indicators of liver function, high Fischer's ratio corn oligopeptides were found to be safe and slightly superior in terms of liver injury repair when compared with a commercial high Fischer's ratio amino acid product. Crude corn peptides (raw material) and skimmed milk powder had no effect on repairing liver injury.