Abstract: The interfacial tension (IFT) characteristics are caused by the interactions among alkaline, surfactant and polymer were investigated in Hejian reservoir (reservoir temperature is 90℃, the total salinity of produced water is 5 192.2 mg/L, the total salinity of flood water is 5 682.6 mg/L, Hejian crude oil).The results demonst rated that the both dynamic and equilibrium IFTs could be lowered to the ultralow magnitude of 10^-2 mN/m as the active concentration of sulfonate CDS-1 was in the range from 0.01% to 0.3%,Unfortunately, the characteristics were diversi ty if Na₂CO₃ is dissolved in 0.05% CDS-1 solution.The equilibrium IFTs increase or decrease unobviously with the increase of alkalinity and could be lowered to the ultra-low magnitude of 10^-2 mN/m.The dynamic IFTs were in the magnitude of 10^-3 mN/m as alkalinity is 0.5% in the alkali CDS-1 solution.The dynamic and equilibrium IFTs increase or decrease unobviously as well as HPAM M2500 is dissolved in the sulfonate CDS-1 or 0.5% Na₂CO₃/0.05% CDS-1 brine.The results provided the basis of selecting surfactant flooding formula in Hejian reservoir.