In order to study on feasibility of dilute polymer systems prepared with polymer-containing oilfield wastewater in the process of polymer flooding in Daqing oilfield，polymer solutions systems the same concentrati on with were prepared，and the viscosity，shear-resistance，viscoelasticity，stability，molecular siz，the injection ability and recovery efficiency of the polymer solutions were measured. The results showed that system prepared with the clean water and diluted with deep treated sewage was superior to the symtem prepared and diluted with wastewater at the polymer concentration of 0，and superior to the system prepared and diluted with biochemical wastewater in the experiment of polymer property test，injection ability and recovery efficiency. Residual polymer in the wastewater could increase the viscosity of the system. The higher the concentration of residual polymer，the higher the property of the polymer system，when the polymer system was at the same preparation of concentration. Dilute polymer systems prepared with polymer-containing wastewater would be widely applied in Daqing oilfield. on comprehensive consideration of polymer injectivity and recovery efficiency，it was advised to prepare and dilute the polymer system with the wasterwater containing 200—400 mg/L residual polymer in Daqing oilfield.