Abstract: The author analyzes the defect of the theory about surfactant/polymer flooding and alkaline/surfactant/polymer flooding in which the low est interfacial tension must reaches 10^-3mN/m. On the basis of plenty of displacement tests, the result of comparing with the enhanced oil recovery values under different IFT shows that the value of interfacial tension, 10^-3mN/m, is not the necessary condition of surfactant flooding, and it can reach the same flooding effect when the value of interfacial tension is 10^-2mN/m. And if only the dynamic interfacial tension can reach 10^-3mN/m, we can acquire a better flooding effect. So the experiment basis can be provided for the wide application of surfactant/polymer flooding.