Abstract: To investigate the anti- fatigue effects of polysaccharides from Hericium erinaceus ( HEP) and monosaccharide composition.Mice were orally administrated with Crude polysaccharide from Hericium erinaceus ( HEPC) , Neutral polysaccharide from Hericium erinaceus ( HEPN) , Acidic polysaccharide from Hericium erinaceus ( HEPA) and distilled water. After 15 days, all mice were subjected to weight- loaded swim test. The exhaustive swimming time, blood lactic acid, blood urea nitrogen and hepatic glycogen were measured. The results showed that HEP especially HEPA could significantly lengthen the swimming time of mice, improve the mice hepatic glycogen reserves, reduce blood lactic acid and blood urea nitrogen content. The HEP has anti- fatigue function and the strongest was HEPA.After PMP derivatization, High performance liquid chromatography ( HPLC) was used for analyzing monosaccharide composition of polysaccharides. The result indicated that HEP was heteropolysaccharide and consisted of mannose, rhamnose, glucose, galactose, fucose and glucuronic acid.