Abstract: Microalgae is a kind of eukaryote which has no root,stem or leaf but can carry out photosynthesis. As microalgae grows fast and has strong adaptability,and its growth is not affected by seasons,the selection of microalgae as the main raw material for extracting carotenoids is increasingly favored by people.Microalgae has various bioactive compounds,for example,pigments,polysaccharides,and long chain polyunsaturated fatty acids. Microalgae is widely used in food,medicine and other industries. The pigment includes carotenoid andphycobiliprotein,and so on. And it is rich in carotenoids,mainly including lycopene,lutein and astaxanthin,etc. Carotenoids have health benefits for the visual system and skin tissue,and can resist adverse environments such as strong light,high temperature or deep water.On the basis of summarizing the main carotenoid species and the distribution and characteristics of carotenoids in microalgae,the biosynthetic metabolic pathway of carotenoids in microalgae,the related genes in the process and the current status of gene cloning are elaborated in this paper,which provide reference for the further research of carotenoid metabolic pathway in microalgae.