The invention relates to a large-scale preparation method of protamine oligopeptide chelated zinc. The method comprises the following steps: by taking mature testis tissues of aquatic organisms as raw materials, hydrolyzing testis nucleoprotein by adopting high-temperature sulfuric acid, carrying out continuous flow centrifugal filtration and multi-stage membrane separation to obtain a protamine oligopeptide solution which has the content of more than or equal to 95%, does not have nucleotide and has high metal zinc chelating activity, then adding zinc salt, stirring, carrying out constant-temperature chelating, and carrying out nanofiltration membrane desalination and impurity removal, thereby obtaining the protamine oligopeptide with high metal zinc chelating activity. The particle size of the nano protamine oligopeptide chelated zinc particles is less than 300nm, and most (more than 80%) molecular weights of the nano protamine oligopeptide chelated zinc particles are less than 1000Da. Although a chemical extraction and metal chelation method is adopted, compared with a commonly used enzymolysis extraction and metal chelation method, the protamine oligopeptide chelated zinc obtained by the method disclosed by the invention is higher in yield, less in time consumption and higher in chelation rate. Meanwhile, the production of large-scale preparation of the protamine oligopeptide chelated zinc does not need special instruments and equipment, the technological method is simple and reliable, the technological process is efficient and flexible, and the protamine oligopeptide chelated zinc subjected to adsorption deodorization and embedding deodorization is good in flavor in the aspects of smell and taste, is easier to serve as a food additive or a nutritional supplement, and is suitable for industrial production. The product is accepted and eaten by vast consumers; and the protamine oligopeptide chelated zinc which is not subjected to fishy smell removal treatment can still be used as a feed additive.