The invention relates to a fish feed produced from cassava starch factory waste residues and orange wastes, and a preparation method thereof. The fish feed comprises, by weight, 60-80 parts of cassava starch factory waste residues, 30-40 parts of orange wastes, 20-30 parts of beer residues, 10-15 parts of bean dregs, 15-20 parts of rice bran, 8-10 parts of soybean meal, 6-8 parts of argy wormwood, 6-8 parts of honeysuckle flower, 2-4 parts of Sowthistleleaf Tasselflower, 2-4 parts of isatis root, 2-4 parts of Oroxylum indicum, 8-10 parts of pine needle powder, 22-24 parts of waste sugarcane molasses, 1.6-1.8 parts of composite bacteria and 0.3-0.5 parts of citric acid. The feed is obtained through combined fermentation of multiple raw materials, the citric acid is used to adjust the palatability, and the argy wormwood, honeysuckle flower, Sowthistleleaf Tasselflower, isatis root and Oroxylum indicum are added and have synergism, so the stress resistance and the resistibility of fish bodies are improved, the disease incidence of fish under a high-density breeding condition is improved, the survival rate of the fish is improved, and the production level and the economic benefit are increased.