In order to clarify the effect and mechanism of different interface properties on EOR，taking the low permeability tight reservoir of Chang 6 as the research object，two self-made surfactants S1（strong modification wettability）and S2（ultra-low interfacial tension） with different interfacial property were selected. Their static and dynamic permeability effects were characterized by nuclear magnetic resonance（NMR），and their oil displacement process was studied by 2.5-dimensional micro model. The EOR effect and mechanism of S1 and S2 were analyzed. The results showed that both S1 and S2 had good enhanced production effects. Imbibition was a process in which water entered small pores to replace oil to large pores. Surfactants could greatly promote the production of small pores. During oil flooding，the dominant channel obviously formed，which could realize wettability reversal. The additional imbibition effect greatly increased the sweep volume and oil washing efficiency，and could disperse the crude oil into small scale state. Among them，the capillary force of S1 with stronger wettability ability was more powerful and had a higher degree of mobilization of small holes，but the recovery rate was slower. While the additional imbibition during displacement was stronger. The S2 with ultra-low interfacial tension could achieve smaller oil phase flow resistance，faster imbibition speed，and faster recovery to reach equilibrium.