In order to achieve water control and oil increment in the highly heterogeneous reservoirs，the micromorphology and size distribution of polymer microspheres PM1 prepared in the laboratory were firstly evaluated. Then the pore throat size distribution of cores was tested via mercury intrusion method and a series of core flooding experiments were carried out coupled with matching coefficients（the ratio of particle diameter corresponding to 25%，50% and 75% in the cumulative size distribution curve to average pore throat size）to investigate the matching between the size of polymer microspheres and pore throat. The results show that polymer microspheres PM1 were micron-sized spherical gel particles. Discrepancies exsist in the average pore throat size obtained from Kozeny theory equation and mercury intrusion method. The migration and plugging modes of polymer microspheres under varying matching coefficients can be divided into complete plugging，high-efficiency plugging，low-efficiency plugging and smooth pass. For reservoirs aiming at near-wellbore profile control，the matching coefficient range corresponding to the high-efficiency plugging mode should be taken into account at first. For reservoirs aiming at depth profile control and oil displacement，the matching coefficient range corresponding to the low-efficiency plugging mode should be used to determine the optimal microspheres size. Compared with the computed results based on Kozeny theory equation，the measurements based on mercury intrusion method can reflect the pore throat size distribution more accurately. Therefore，in the actual application，we suggest that more focus should be put on the matching coefficient range based on mercury intrusion method.