Abstract: According to the composition of wastewater produced from polymer flooding in Bohai JZ9-3 Oilfield, influences of produced polymers with different molecular weight, concentration and hydrolytic degree on the apparent viscosity, particle sizes of oil droplets, Zeta potential, dynamic interfacial tension, equalize interfacial tension and interfacial dilatational properties were measured. The results indicated that the produced polymer with low molecular weight could improve the apparent viscosity of wastewater, and the Zeta potential of O/W emulsion and the oil-water interfacial film strength were increased after adsorption of polymer in oil-water contact. Consequently the wastewater emulsion stability was increased, and the coalescence efficiency of oil droplets in wastewater was decreased greatly, so that the difficulty of polymer-contained sewage reaching standard became harder.