Abstract: The article improved Phenol-Sulphate acid method on the base of experiment. If we adopt traditional Phenol-Sulphateacid method, the deference of parallel sample’s absorbency is larger and the accurate and reproducible is worse. We used the newmethod to checked inspected wavelength, color test time, color test temperature, stability, reproducible, recovery ration,linearitys cope andt he limito f determination.A lsow ee xamined polyaccharideo f purified Tremellap olysaccharide, soluble starch, Polyporus umbellatus ploysaccharide, and laminarin, and other polysaccharide samples. All what we have done prove that theimproved method can simplify the operation, increase accurate and reproducible.

Key words: Phenol-sulphate acid method, color test, polysaccharide, temperature