The oil/water interfacial properties of crude oil emulsions formed by alkaline/surfactant/ polymer(ASP) flooding in the Daqing Oilfield were investigated in this paper by the measurement of interfacial tension,interfacial shear viscosity and Zeta potential of the oil/water system.The result showed that both NaOH and Na_2CO_3 could react with acid substances in the crude oil to produce interfacially active components,which are adsorbed on the interfaces between the aqueous phase and oil phase, resulting in a decrease of the interfacial tension,negatively charging the surface of oil droplets,but making little change in the interfacial shear viscosity.For the same ionic strength of NaOH and Na_2CO_3, the interfacial tension of NaOH solution-crude oil system is lower,but the interfacial shear viscosity of NaOH solution-crude oil system is higher,than that of Na_2CO_3 solution-crude oil system.The negative value of the Zeta potential on the surface of the oil droplets is large.Accordingly,the O/W emulsion of NaOH solution-crude oil system is more stable than that of Na_2CO_3 solution-crude oil system. The oil / water interfacial properties of crude oil emulsions formed by alkaline / surfactant / polymer (ASP) flooding in the Daqing Oilfield were investigated in this paper by the measurement of interfacial tension, interfacial shear viscosity and Zeta potential of the oil / water system. The result showed that both both NaOH and Na_2CO_3 could react with acid substances in the crude oil to produce interfacially active components, which are adsorbed on the interfaces between the aqueous phase and oil phase, resulting in a decrease of the interfacial tension, negatively charging the surface of oil droplets, but making little change in the interfacial shear viscosity. For the same ionic strength of NaOH and Na_2CO_3, the interfacial tension of NaOH solution-crude oil system is lower, but the interfacial shear viscosity of NaOH solution-crude oil system is higher, than that of Na_2CO_3 solution-crude oil system. The negative value of the Zeta potential on the surface of the oil droplets is large. Accreditedly, t he O / W emulsion of NaOH solution-crude oil system is more stable than that of Na_2CO_3 solution-crude oil system.