The fish oil consists of a variety of unsaturated fat,generally extracts from fish scraps by the steps of steaming,crushing and separation. Fish oil is rich in triglycerides,glycerol ether phosphate,lipids,fat-soluble vitamins,and protein degradation products,etc. Microencapsulation technology can significantly improve the antioxidant stability of fish oil by wrapping a tiny amount of material in a polymer film. Supercritical carbon dioxide (SC-C) and spray-drying are being evaluated most favorably in fish oil processing. Factors influencing the microencapsulate efficiency are discussed including emulsifier density,collagen proportion,solid proportion,inlet air temperature and the ratio of core material to wall material. And the effect of microencapsulation can be measured by the effect of embedding,and SEM (scanning electron microscope) can be used in evaluating the ultrastructure of encapsulated fish oil.