The antioxitation function of Hericium erinaceus polysaccharide which was yielded by liquid fermentation was studied. The resules showed that Hericium erinaceus polysaccharide can improve the content of serum lysozyme to some extent. And it can obviously enhance the contents of SOD and CAT of serum and cerebrum and liver. And it can descend the contents of MDA of serum and cerebrum and liver to some extent. The Hericium erinaceus polysaccharide has the important antioxitation function.