Chitosan, also known as deacetylated chitin, is obtained by deacetylation of chitin widely existed in nature. Its chemical name is polyglucosamine (1-4) - 2-amino-B-D glucose. Since 1859, when French Rouget first obtained chitosan, the excellent properties of this natural polymer, such as biological functionality and compatibility, blood compatibility, safety, microbial degradation, have been widely concerned by all walks of life, and significant progress has been made in the application research in medicine, food, chemical industry, cosmetics, water treatment, metal extraction and recovery, biochemical and biomedical engineering and many other fields. Gold chitosan high-density chitosan has been reported to reduce blood lipid and blood glucose in patients. At the same time, chitosan was listed in the national food additive use standard GB-2760 as a thickener and coating agent