The Daqing field, discovered in 1959, is the largest oil field in the People＇s Republic of China, with original oil in place exceeding two billion tons. The heterogeneity of the reservoirs and the viscosity of the oil have resulted in a moderate displacement efficiency and in a high water-cut in the production. In order to increase the recovery, polymer injection was tested in two pilots between 1987 and 1992 after laboratory and reservoir studies. Both pilots proved highly successful and led to the decision to extend polymer injection to the whole field. This article presents the whole history of the Daqing Polymerflooding Project, from the preliminary studies to the extension.