Abstract: Due to the special accumulation mode and reservoir characteristics of shale oil reservoirs, the reservoirs are very dense, with nano-scale pores and throats are developed, which results in high flow resistance of crude oil and low overall recovery of shale oil. Through the study of contact angle, interfacial tension and oil washing tests, the mechanism of interaction between different types of surfactants and shale oil rocks as well as crude oil is clarified, in order to judge whether the surfactant can be used to improve shale oil recovery. The results show that surfactant can change the surface wettability of shale oil rocks and reduce the interfacial tension, and finally realize the effect of improving the efficiency of oil washing.