In this paper, it investigates the effect of complexing agent on the viscosity and oil-water interfacial tension of partially hydrolyzed polyacrylamide HPAM and linear alkyl betaine BH systems, and discusses the method of utilizing complexing agent as additive to improve the increasing viscosity ability and interfacial property of polymer and surfactant flooding system in high salinity reservoir. It has been found that the viscosity of 1 800 mg/L HPAM may be increased by more than 80%, and the minimum of dynamic interfacial tension between BH surfactant solution and crude oil may be reduced from 10-2 mN/m magnitude to ultralow level by addition of only 50 mg/L complexing agent in salt water containing NaCl 6 500 mg/L, CaCl2 890 mg/L and MgCl2 520 mg/L respectively, which is also suitable for HPAM and BH mixed system. By studying the variation of aging viscosity and dynamic interfacial tension, the action mechanism of complexing agent is further analyzed.