The invention belongs to the field of food processing, and particularly relates to nutritional chicken soup rich in umami peptide and a preparation method of the soup. Chicken breast is unfrozen, cleaned, mashed, added with water and stirred into feed liquid, compound protease is added for proper enzymolysis, and supernate is centrifugally separated to perform Maillard reaction. By the aid of proper enzymolysis technology, the dissolution rate of chicken protein is increased, chicken enzymatic hydrolysate is rich in amino acid and micro-molecule polypeptide, thermal reaction chicken soup subjected to the Maillard reaction keeps original fragrance and delicacy of traditional chicken soup, free amino acid reaches more than 20 times that of the traditional chicken soup, the micro-molecule polypeptide and the like are greatly increased, and the nutritional chicken soup is more easily digested and absorbed by human bodies. Chicken soup boiling time is shortened, and industrial production is more easily realized.