Abstract: Squalene is a precursor of several common sterols, which has important biological activities and food and drug value. Due to the protection of marine wildlife and fishery resources, the commercial production of squalene is greatly limited. It is very important to find new sustainable sources for the production of squalene. This research mainly expounded the biological activity, source and application of squalene, analyzed the biosynthetic pathways and extraction methods of squalene from different biological sources, and put forward the economic feasibility for green production of valuable squalene by microorganisms (especially for microalgae), which aim to provide a theoretical basis for the industrial production and application of squalene.