A series of studies have been carried out on the chemical total synthesis route of astaxanthin at home and abroad. Hoffmann-Roche and BASF are two major companies in chemical synthesis of astaxanthin. The two companies use chemical synthesis to produce Astaxin with similar synthetic routes, using C9+C6→C15, 2C15+C10→C40 route. Hoffmann Roche Company uses 6-oxoisophorone as raw material , firstly uses acetone and formaldehyde to undergo aldol condensation under weak alkaline conditions to lose water to form α-β unsaturated butenone, and then generate α-β unsaturated butenone with acetylene. 1,2-nucleophilic addition generates tertiary hexacarbyne alcohol, which is rearranged under the action of sulfuric acid, protecting the hydroxyl group of the product to react with 6-oxoisophorone, and finally, under the action of a strong base, a bilateral Synthesis of astaxanthin by Wittig reaction. The intermediate hexacarbyne tertiary alcohol synthesized in the synthetic route of BASF does not undergo acidification and rearrangement first, but protects the hydroxyl group and undergoes a series of transformations with 6-oxoisophorone. row, and finally obtain the target product astaxanthin. The domestic synthetic route of Astaxin is different from the foreign synthetic route. Astaxanthin is prepared by the synthetic route of C13+C2→C15, 2C15+C10→C40. He used α-ionone as raw material, treated with m-chloroperoxybenzoic acid, after a series of intermediate conversion processes, acidified and rearranged under the action of hydrobromic acid, and then reacted with triphenylphosphine to generate 15-carbon triphenylene base phosphonium salt, and finally undergo a bidirectional Wittig reaction to generate astaxanthin. The uniqueness of the synthetic route lies in the use of a new method to synthesize the key intermediate C15 compound, which has easily available starting materials, high reaction selectivity and high overall yield. The Witting reaction is a characteristic reaction of the total synthesis route of Astaxin. Such synthetic route has the advantages of simple process and low cost. Although the two routes of Hoffmann-Roche and BASF are very complex, the production process is long, the control of the intermediate process is difficult, and the requirements are strict, but the synthesis cost is low, the price is cheap, and industrial production has been realized. The most important industrial source of astaxanthin supply in the market.