Nano-emulsion is a kind of delivery system for functional ingredients, which can enhance the stability, solubility, and bioavailability of bioactive compounds. Several macromolecules such as polysaccharides and proteins can be used as emulsifiers to prepare nano-emulsion with high safety, which have great application potential in food industry. In this paper, the selection of core materials, oil phases and emulsifiers, and their effects on the characteristics of nano-emulsion were summarized, and the preparation methods, physicochemical properties and application prospect of nano-emulsion were.also discussed.