Abstract: ASP flooding is a tertiary oil recovery technology which can greatly improve oil recovery, the system of which is composed of polymer, alkali and surfactant. The oil displacement mechanism is relatively complex and there are many influencing factors. Therefore, through physical simulation flooding experiment, the displacement rate parameters in ASP flooding experiment are studied in depth. The experimental results show that there is an optimum displacement rate in ASP flooding, which is 0.10～0.20 mL/min in natural cores and 0.30～0.60 m L/min in artificial cores. The optimum displacement rate is positively correlated with core permeability. Different composite systems take different time to reach the minimum interfacial tension value, and have different influence degrees on recovery under different displacement rate. The change of displacement rate has a great influence on the displacement effect of the composite system with small natural cores and gentle interfacial tension decline.