The present invention discloses a method for the preparation of a protein peptide, peptide powder prepared thereby, and use of the peptide powder in hypouricemic food products or health care products. The peptide powder is capable of inhibiting the activity of xanthine oxidase and effectively reducing uric acid. The method in an example of the present invention comprises: mincing the tuna, heating with steam or water to obtain a pretreated tuna, enzymolysing the pretreated tuna, deactivating the enzyme, centrifuging, removing impurities to obtain a supernatant, concentrating, and drying to obtain the peptide powder of interest.
