Fish oil has a wide range of scientific research and application value because it is rich in polyunsaturated fatty acids needed by human body. This article focused on its n-3 PUFA enrichment process， steady state technology and biological activity， expounded the advantages and disadvantages of different methods， analyzed the feasibility of industrial production， and prospected the future development trend of fish oil industry， in order to provide a theoretical basis for the rational， healthy and sustainable development of fish oil resources.