The invention discloses a nano self-emulsification system. The nano self-emulsification system is characterized by being prepared from a component (a) and a component (b): wherein the component (a) is a surfactant containing nanoparticles, the component (b) is an emulsifier containing an oil phase. The oil phase is a mixture of an emulsifier, polyethylene glycol and a mineral oil, the weight ratio of the nanoparticle hydrosol to the oil phase is 100:(30-60), preferably 100:(30-50) and more preferably 100:(35-45). The invention further provides a preparation method of the nano self-emulsification system.