The invention provides a preparation method of a feed capable of improving intestinal functions of prawns. The preparation method comprises the following steps: S1, mixing and pulverizing orange peel,garlic, fennel, origanum vulgare, sargassum and hawthorn, placing the mixture in a pressure tank, insulating and taking out the mixture; refluxing the mixture in an ethanol solution, separating the mixture to obtain filtrate and filter residues, and condensing the filtrate to obtain an extract; S2, mixing and fermenting bifidobacterium, lactobacillus, bacillus natto, brewer's yeast, molasses andwater to obtain an activated strain; S3, mixing and fermenting corn flour, silkworm chrysalis, the filter residues and the activated strain to obtain a first fermentation broth; and adding red dates,fructus hippophae and clam shell powder in the first fermentation broth and continuing fermenting, and filtering and drying to obtain a second fermentation broth; and S4, mixing the second fermentation broth and the extract, stirring uniformly, granulating and drying to obtain the final product. The orange peel, the garlic, the fennel and the like are used as the raw materials, can prevent intestinal flatulence of the prawns, assists in digestion and inflammation diminishing, and can control and prevent intestines problems of the prawns.