For sandstone reservoirs with extremely high water content, the Volume of Fluid (VOF) method is able to trace the dynamic changes of multiphase interface and reproduce the physical process of microscopic seepage. The influence of different displacement pressure gradients on the microscopic occurrence characteristics of remaining oil and water flooding recovery is studied. The influence of displacement pressure gradient on water flooding recovery is revealed by analyzing the seepage characteristics and remaining oil occurrence state in microscopic pore structure. The increase of displacement pressure gradient can break through capillary force of small throat, form a new seepage channel, and increase the water flooding recovery. The viscosity and wettability of crude oil affect the recovery degree under different pressure gradients.