Abstract: The major development sequence in Shanshan oilfield is the Sanjianfang reservoir of Jurassic, with effective porosity of 12.8% and average permeability of 6.2 mD. The indoor physical simulation experimental research of polymer flooding is made for EOR in Shan?shan oilfield. This paper determines the concentration?viscosity relationship of the polymer solution with relative molecular mass of 1200×104, 830×104, 620×104, integrated with the real development state of Shanshan oilfield, preferentially screens the polymer solution with relative molecular mass of 830×104 and mass concentration of 1 250 mg/L. The experimental results show that the rest core polymer flooding’s recovery percents can reach over 12%, except for the recovery percent of 7.2% using the core sample with permeability of 0.43 mD