Polymer flooding widely used in oilfields for a long time. As a result，there are serious plugging of oil wells and the liquid volume decreased，which seriously affects the further development of reservoirs after polymer flooding. For polymer flooding reservoirs in Shengli oilfield，X-ray diffractometer，scanning electron microscope and other technical means were used to analyze the composition of oil well plugging products. By simulating different plugging fluids and near-well reservoir conditions，the plugging degree and main controlling factors of oil well plugging were studied. The results showed that the plugs in the oil wells of polymer flooding reservoirs were mainly polymer aggregates（65.6%）that were cross-linked and embedded to adsorb formation mineral salts and clays，followed by formation sand particles and cements（17.8%），and crude oil（16.6%）. The plugging of porous media that caused by the formation of sand particles was the main controlling factor of plugging near the oil well. The polymer agglomerates that formed by polymer derivative cross-linking and adsorption agglomeration aggravated the degree of blockage of oil well. Based on the guidance of the research on plugging mechanism of polymer flooding reservoirs，the integrated prevention and control program of oil well plugging and sand control，which was composed of crude oil cleaning and oxidative degradation of polymer micelles in near well，and effective sand consolidation control in far well，had good application effects. The average single well extraction was 86.8%.