Surfactant can achieve the purpose of decompression and augmented injection in low permeability reservoirs by reducing interfacial tension and emulsification. The effect of emulsification rate and interfacial tension on the decompression was studied through macroscopic and microscopic methods. The synergy between the interfacial tension and emulsification rate were analyzed. The results show that decompression can be reached when the interfacial tension is less than 5.25 mN/m，and the effect is more significant with the reduction of interfacial tension. If the interfacial tension reduces，oil recovery may increase；but when the interfacial tension decreases to 10-1 mN/m，impact on the oil recovery is limited. When it arrives at 10-2 mN/m，the surfactant cannot completely eliminate the additional resistance of residual oil in the flow channel yet. When the emulsification rate of the surfactant is greater than 0.11 mL/min，decompression effect is obvious. More pres?sure drop appears with the emulsification rate improving. But when it is greater than 0.42 mL/min，it has little effect on the pressure. The oil recovery increases with the emulsification rate improving until l0.21 mL/min. But when it is higher than 0.21 mL/min，higher emulsification rate has smaller effect on the oil recovery. Therefore，the emulsification rate of suitable surfactant system should be as short as possible and thus let oil emulsified completely to gain rapid expansion of sweep area.Then the interfacial tension is reduced to improve displacement efficiency at lower pressure and thus，higher oil recovery.