Blue foxes are widely farmed in China because of the value of their fur, which can also be used as experimental animal models. Now China has become one of the largest blue fox breeding countries in the world. China's Ministry of Agriculture and Rural Affairs has ordered a total ban on antibiotics in feed by the end of 2020. Improving the growth performance of blue foxes and enhancing the body's resistance to disease are the key links of blue fox breeding. In recent years, many studies have shown that functional additives such as Chinese herbal medicine additives and aminopolysaccharide can improve the disease resistance and production performance of cultured animals, as well as prevent diseases and reduce mortality. There are no relevant reports on the application of aminopolysaccharide in blue fox feeding. This project aims to study the effects of polysaccharides on growth performance, immune indices and intestinal microflora of blue foxes. It provides a basis for the development of efficient, safe and green feed additives for blue fox.