The one-dimensional nuclear magnetic resonance (NMR) method cannot distinguish the relaxation signals of oil and water during flooding, so longitudinal relaxation-transverse relaxation (T₁-T₂) two-dimensional NMR method was used to distinguish the type and distribution of fluids in the cores. The enhanced oil recovery (EOR) of the SP flooding system consisting of polymer BRH-325 and surfactant GSS-A was studied by flooding experiments at 65, 70, 75 ℃, respectively. T₁-T₂ two-dimensional NMR method was used to visually study the flooding law and distribution characteristics of oil and water in the cores. And the experimental measurement results were compared with the NMR measurement results. The results indicate that the SP flooding has the most significant effect on EOR at 70 ℃. Therefore, T₁-T₂ two-dimensional NMR can easily and clearly distinguish the relaxation signals of oil and water during flooding.