This article mainly discusses the target reservoir after injection of medium and high molecular weight polymer into different well groups under the condition of relatively serious water accumulation interference. Based on the analysis of field data, the effectiveness, water cut change and stage recovery degree of oil wells around the well group are summarized. The appropriate parameter setting for the second oil reservoir well group are obtained to ensure the quality and the effect of the injected polymer, thereby greatly improving the recovery rate and the development benefit of the target block. The results show that the oil layer is more suitable for injecting 1 200~1 600 million molecular weight polymers, and the viscosity should be in the range of 30~50 mPa∙s; in the case of similar background conditions, the medium fraction is more suitable for the use of thin⁃difference oil layers, the high concentration of water in Class II oil reservoirs has a large decline in water cut, and the effect of increasing oil production is very good. The adoption of this technology can increase oil recovery, which is more than 10 percentage points higher than the conventional concentration.