Abstract: By physical simulation parallel core displacement test, the range of EOR by gel system will obviously decline with the increase of polymer concentration in the conditions of core permeability ratio of 60 times, polymer concentration of 200~800 mg/L and total chromium cross?linked polymer gel injection of 0.2 PV. The result shows that the ultra?low concentration polymer organic chromium gel system has high viscosity and stability after injecting into the reservoir, avoiding the affect of many uncertain factors caused by the polymer gel injecting into the reservoir on the gel system. It is concluded that the duel?tube parallel core displacement test can improve EOR by 9%~16%