Abstract: Astragalus polysaccharide is water-soluble neutral heteropolysaccharide. Studies have demonstrated that dietary supplementation of astragalus polysaccharide is able to improve the antioxidant capacity,immune function,production performance and intestinal development of animals. Astragalus polysaccharide also shows antibacterial activity. The molecular structure,composition,extraction technology and biological activities of astragalus polysaccharide are reviewed in this paper,so as to provide theoretical basis for its further development and utilization as a feed additive.