Abstract: Oxidation reaction in food is related to chronic diseases and rancidity, shortening the nutritional value and shelf life of products. In recent advances, the amino acid, sort order and spatial conformation of the antioxidant peptides is wildly reported. The structure-function relationship of antioxidant peptides has become the main factors on the determination of the antioxidant mechanisms. However, compared with the significant antioxidant effect of the peptides from land animals, such structure-function relationship of the antioxidant peptides in the fish, which is rich in proteins, is seldom reported. Therefore, antioxidant mechanisms of the peptides from fish, such as scavenging the intracellular reactive oxygen species in vivo, scavenging the free radicals in vitro and chelating the pro-oxidant metal ions is summarized in this review. The structure-function relationship between the primary structure and secondary structure on the antioxidant activity of fish peptides is provided. Moreover, the effects of non-polar amino acids, polar uncharged amino acids, polar positively charged amino acids and polar negatively charged amino acids are further reviewed. The review would provide a guide for the application of antioxidant peptides, and expand the food market for such products.