Abstract: Low interfacial tension can be formed by surfactant without alkali/polymer oil displacement system and crude oil.Furthermore,problems such as equipments corrosion,emulsion and so on are solved and difficulty in ground processing of produced liquids is decreased for no alkali in formula.By Laboratory,formula of binary complex system is selected preferentially,and some aspects such as compatibility,viscosity stability,thermal stability,salt-resistant property,anti-hard water performance,emulsion property,and so on between the formula and oil-water conditions in experimental area is evaluated and the properties accord with the requirements in various aspects.Meanwhile,physical simulation investigation is done by the combination system.It concludes that contributions of oil washing ratio in recovery efficiency occupy a part of combination flooding recovery efficiency,however,polymer expanding the volume occupies certain proportion in recovery efficiency.In a word,it is coordination of them that enhances oil displacement efficiency.