Abstract: In this paper, the change of the backscattered light intensity of the wastewater in ASP flooding simulation was studied by using the Turbiscan stability analyzer, and the droplet kinetic stability information was obtained. Meanwhile, the stability constant value (TSI-1) was used to make out how the oil displacement agent content in the sewage affect the wastewater stability. Furthermore, under the different oil-displacing agent content, the interface properties of droplets, particle sizes, electrical properties, interfacial film strength and viscosity of water phase were studied. Then the mechanism how the oil displacement agent act on the stability of the wastewater was analyzed. Finally, the results show that surfactants and alkali can lower the oil-water interfacial tension, reduce the droplet size, increase the Zeta potential and the film strength, but they have little effect on the viscosity of the water phase; polymer mainly increases the oil droplet's Zeta potential and film strength and improves the water phase viscosity dramatically. These effects prevent small droplets from transforming into large droplets, slow down the coalescence of large droplets and lower the stratified speed. As the concentration of the surfactant, alkaline and polymer in sewage increasing, the stability of the wastewater will be enhanced.