The swing radius andhydrodynamic sizetypically are used to characterize the flow size of the polymer solutions in porous media when the matching relationship between polymers and formations is studied.This characterization has shortcomings because polymers are aggregates of manypolymer moleculesin the percolation process.Thus, the concept of a hydrodynamic characteristic size of polymer was proposed, and its factors were studied.In respect to matching relationship, flooding verification experimentswith natural cores from the target block were conducted, finally, the matching relationship between different polymer solutions and different permeability cores was set up and combined with the pore throat radius obtained from core pressure mercury data.The experimental results of microporous membrane filtration indicate that the hydrodynamic characteristic size of polymermaintained a good nonlinearrelationship with polymerviscosity;the value increased as the molecular weight andconcentration of the polymer increased, and as the dilution watersalinity decreased.Additionally, thehydrodynamic characteristic size decreased as the pressure increased, so the hydrodynamic characteristic size should be determined based on the pressure of the block.Core flooding experiments support the assertion that when the pore throatradius is more than 10 timeshe hydrodynamic characteristic size, the polymer solution does not block the formation.On the contrary, plugging occurs.Finally, matching relationship plates between different permeability reservoirs of the target block S and different polymer hydrodynamic characteristic sizes wereestablished according to the matching relationship, which can provide a theoretical basis for adjusting polymer flooding in reservoirs in the target block S.