This paper is presented to clarify the influence of polymer flooding on the remaining oil distribution and development characteristics of offshore oilfield under the control of intra-layer heterogeneity. According to the principle of similarity and referring to the actual reservoir and fluid characteristic parameters of the oilfield, laboratory simulation experiments of water flooding and polymer flooding under different heterogeneity are carried out. The experimental results show that the length of anhydrous recovery period is inversely proportional to the degree of heterogeneity in the process of water flooding. When the heterogeneity is strong, the remaining oil in the low permeability layer is enriched, and the coefficient of variation is inversely proportional to the water flooding recovery. Compared with the water flooding development mode, polymer flooding can effectively inhibit the channeling effect in the high permeability layer, and effectively expand the spread volume. The oil recovery rate of different heterogeneity models during the same period can be increased, the final recovery rate can be increased by 13.01%~16.69% compared with water flooding. The recovery rate of polymer flooding is inversely proportional to the permeability grade. For the strong heterogeneous reservoir, there is still a lot of remaining oil in the low permeable layer after polymer flooding, so the strategy of tapping the adjusted well should be adopted. For the weak heterogeneous reservoir, the combination of regulation and plugging is adopted to change the direction of the main flow line. Through the implementation of targeted adjustment and potential tapping measures, the polymer flooding development effect of the oil field is obviously improved, which provides reference for offshore oil fields development of the same nature.