Abstract: The emulsion is widely used in the fields of food science, petrochemistry, cosmetics and agrochemistry. The stability is the key factor for function exertion and service life. Therefore, the rapid and accurate characterization of emulsion stability has been of concern for a long time. Emulsion oil in water is one pesticide formulation based on the emulsion with high efficiency, low toxicity and environmental safety. In this paper, the application and research of emulsions in food science and petrochemistry were introduced. In particular, the main characterization methods in the preparation and utilization for emulsion stability, such as droplet size and distribution measurement, conductivity measurement, microstructure research, pseudo-ternary phase diagram research and the electric properties of the droplet surface research, were described. Furthermore, the application of these characterizations methods in pesticide emulsions was summarized. We are aimed to provide ideas to shorten development cycle and improve stability for pesticides emulsion oil in water.