Abstract: Astaxanthin is an important secondary carotenoid with extremely strong antioxidative properties and is widely used in food, chemicals, pharmaceuticals, aquacultures and so on. The synthetic methods of astaxanthin include chemical synthesis and biosynthesis. Chemical synthesis of astaxanthin is the source of commercial astaxanthin, while biosynthesis of astaxanthin is safer and more popular in food and health products industries. This review summaries chemical synthetic and biosynthetic pathway of astaxanthin, with emphasizing on the biosynthetic pathways of astaxanthin, key genes involved in biosynthetic and metabolic network of astaxnathin in microorganisms and plants. The research progress of using random mutagenesis, metabolic engineering, enzyme engineering and other methods to improve the synthesis and accumulation of astaxanthin in bacteria, yeast, and marine eukaryotic microorganisms is summarized. This article can provide theoretical guidance for the research on the efficient synthesis of astaxanthin.