Low permeability reservoirs have the characteristics of small pore throat radius，low permeability and poor water absorption，resulting in unsatisfactory chemical flooding effect. Aiming at this problem，propylene oxide and ethylene oxide were introduced into dodecyl alcohol and sulfonated to obtain alcohol ether sulfonate（DP6E6S）. Then，a compound system of DP6E6S and C₁₆-carboxybetaine（PNC）surfactant was constructed. The surface/interface，aging，adsorption，wettability and emulsification properties of the system were evaluated. Finally，the injection enhancement performance of compound system was explored by core flow experiment. The results showed that PNC and DP6E6S exhibited strong synergistic effect. Compared with a single surfactant，the compound system effectively reduced the critical micellar concentration and surface tension，while enhanced the stability and adsorption resistance of emulsion. The PNC/DP6E6S surfactant system with a molar ratio of 1∶1 and 2∶3 demonstrated strong anti-aging properties. It could maintain the oil-water interfacial tension to 10^-3 mN/m in a wide range of salinity（5%—10%）. After aging at 60 ℃ for 30 days，the oil-water interfacial tension had no obvious change. With the increase of salinity，the emulsion prepared by the compound surfactant would undergo phase transition from Winsor I to Winsor Ⅲ and then to Winsor Ⅱ. The medium phase emulsion exhibited a larger volume and better stability. The average particle sizes of the compound surfactant emulsion with ratios of 1∶1 and 2∶3 reached the minimum value（7.52 and 10.01 μm）at NaCl concentration of 8%. In addition，the compound surfactant solution at these ratios also demonstrated excellent solubilization effect，with oil solubilization up to 68 and 64 mL/g，respectively. The PNC/DP6E6S compound system，with low interfacial tension and high wettability angle，was beneficial for reducing pressure and increasing injection in low permeability reservoir. Compared with water flooding，the depressurization rate of 1∶1 and 2∶3 surfactants could reach 28.9% and 23.9%，respectively，meanwhile the recovery efficiency could be increased by 21.85 percentage points and 18.92 percentage points. The ability of the compound surfactant system with a 1∶1 ratio of PNC to DP6E6S in reducing capillary forces was superior to that with a 2∶3 ratio，resulting in better pressure drop reduction and enhanced oil recovery.