The invention relates to an immune-enhancing feed and a preparation method thereof. The immune-enhancing feed consists of gulfweed, sargassum thunbergii, cured kelp powder, cured shrimp meal, scallop meal, kaido crab apple powder, extruded soybean peptide, kaido crab apple shell powder, a nutritive element mixture and an immune-enhancing additive. The preparation method comprises the following steps: firstly, preparing the immune-enhancing additive; secondly, preparing the nutritive element mixture; and finally, adding the immune-enhancing additive and the nutritive element mixture into the gulfweed, the sargassum thunbergii, the cured kelp powder, the cured shrimp meal, the scallop meal, the kaido crab apple powder, the extruded soybean peptide and the kaido crab apple shell powder, and mixing to prepare a product. According to the immune-enhancing feed and the preparation method thereof, the preparation method is simple and is easy to operate, and the immune-enhancing feed can enhance the immunity of a stichopus japonicus organism and improve the resistance against the diseases of stichopus japonicus.