In order to explore the new type of biosurfactants which can be applied to the EOR, one kind of lactone sophorolipid biosur?factant was chosen as an oil displacing agent for evaluating the drive oil properties through studying its physical simulation experiment and physical and chemical properties, such as critical micella concentration value (CMC), stability to salinity and temperature, the emulsification value, the effect of core adsorption and physical simulation experiment. The results of physical and chemical properties experiments indicated that the biosurfactant had the good properties in emulsification and reduction of the interfacial tension and surface tension in the complex environment of oil reservoir, such as the high temperature and high salinity reservoir environment. The CMC of the biosurfactant is 100 mg/L, and this kind of biosurfactant could make surface tension of distilled water reduced to 37.1 mN/m and the interfacial tension reduced to 3.07 mN/m. The effective concentration of flooding is 10 mg/L; with the increase of the mass concentration of the surfactant, the oil displacement efficiency increases in double; And, the biosurfactant oil displacement efficiency can reach 7.85% when the concentration of biosurfactant is 10 000 mg/L , which shows good oil displacement performance; By doing experiments, we also found that the quartz sand adsorbed little lactone sophorolipid, which indicates that the lactone sophorolipid biosurfactant is a kind of economic biosurfactant. In Summary, the lactone sophorolipid biosurfactant has great prospects in the field of oil production.