Polysaccharides are widely found in nature, mainly divided into three kinds of plant polysaccharides, animal polysaccharides and microbial polysaccharides. In recent years, the antioxidant activity of polysaccharide has become a hot spot in the field of polysaccharide research. Polysaccharide is one of the active ingredients of many medicines, which has the functions of increasing antioxidant enzyme activity, eliminating free radicals, inhibiting lipid peroxidation and protecting the biofilm, anti-oxidation and anti-aging effects. The preparation methods, main chemical structures and antioxidant activities of important traditional plant polysaccharides from different sources were investigated and discussed.