In order to establish cocoa adulterating detection methods,polysaccharide contained in cocoa powder was extracted by Ultrasound assisted method,then hydrolyzed with sulfuric acid solution,and finally derivatized with 1-phenyl-3-methyl-5-pyrazolone(PMP) to get cocoa polysaccharide fingerprints by high performance liquid chromatography(HPLC).According to the relative peaks areas of the common peaks,adulteration detection of cocoa powder was attempted successfully by system clustering analysis(HCA) method.The results showed that cocoa powder adulterated with more than 15% cocoa shell could be identified by this method.