Based on the geological characteristics of Ng63+4 sand group in the west 7th block of Gudong oilfield, two-dimensional flat areal models are designed for the water flooding experiment. A real-time monitoring system is set up to measure and represent the distribution of pressure and water saturation in the model, and the relationship between water cut increasing rate and distribution of pressure and saturation is revealed. According to the distribution of pressure and water saturation, the velocity distribution and flow line of oil-water two phases in the model are derived. By adjusting the flow line, the influence of supply boundary and pressure gradient on the distribution of water saturation at extra high water cut stage is studied. The distribution of water saturation predicted by the particle migration model is compared with the experimental results, and it is considered that long-term water flooding and pressure fluctuation will change the permeability and wettability of the reservoir, which will lead to the change of oil-water two-phase relative permeability curve. By revising the relative permeability curve, the water saturation distribution with high similarity to the experimental measurements is predicted, which provides a new way for predicting remaining oil distribution of high permeability reservoir at extra high water cut stage.