Accurate understanding of the microscopic occurrence state of water flooding residual oil in porous media is of great significance for improving the development effect of water flooding and enhancing the recovery factor of water flooding in high water cut oil fields. Based on the verification of the Volume of Fluid (VOF) method, influence of physical property conditions and displacement modes on the microscopic occurrence characteristics and recovery factor of remaining oil in ultra-high water cut sandstone reservoir was studied by making full use of its advantages of tracking the dynamic change of two-phase interface and reproducing the physical process of microscopic seepage. By analyzing the microscopic seepage characteristics of typical pore structures and the stress of remaining oil, mechanism and law of different types of microscopic remaining oil are revealed: The increase of displacement velocity and the change of displacement direction make the distribution of microscopic remaining oil dispersed and the recovery efficiency is improved in different degrees under the condition of water and humidity; As the oil is wet and the viscosity ratio is high, the capillary resistance and viscosity are great, the remaining oil is mostly clustered and porous, and the recovery degree is relatively low.