In order to quantitatively describe the changes of adsorption retention pore volume and Inaccessible pore volume in polymer flooding process, and provide an important basis for the optimization of Bohai J oilfield polymer flooding project, the experimental that research on polymer flooding and test of polymer output concentration is carried out according to the similarity principle, referring to the characteristic parameters of Bohai J oilfield. The experimental results show that there is preferably linear relationship between polymer solution concentration and absorbance， under the same concentration of injection polymer solution, the adsorption retention pore volume and inaccessible pore volume increase with decrease of core permeability， for the cores of same permeability, the adsorption retention pore volume and inaccessible pore volume increase with the increase of polymer injection concentration. The adsorption retention pore volume is about 0.04~0.02 PV and the inaccessible pore volume is about 0.12~0.22 PV of Bohai J oilfield.