Abstract: In recent years, the rapid development of nanotechnology has opened up new application prospects for modern plant protection. As a novel nano-carrying drug system, nanoemulsion with advantages of good dispersion, wetting, slow release, high efficiency, and small particle size, improves the attachment, deposition and penetration of pesticides on the target surface, effectively improving the utilization rate of pesticides, reducing the use of pesticides, and the risk brought to the environment. This paper introduces the composition and preparation methods of nanoemulsion and reviews the research and application in the field of pesticides. At the same time, the controversial boundary between nano-emulsion and microemulsion is discussed, and the development prospect of this field is addressed to provide a reference for the preparation of nano-emulsion with excellent performance.