Abstract: Sewage has a significant effect on the viscosity of polymer and a direct influence on the oil displacement result and economic benefit of polymer-injection engineering.This paper presented that the main factors that influenced the viscosity of polymer are oils,impurities, and diatomic iron in sewage and flocculates (positive) used for sewage disposal according to field and laboratory test. The water quality criteria under the condition of polymer water flooding test in Menggulin were also determined.