The digital core image was captured based on CT scans, and the lattice boltzmann method was verified through the simulation of wetting degree of droplet on the solid wall. By using the lattice boltzmann method, it simulates water phase and oil–water two phase flow process separately in pore scale, acquiring fluids distribution in porous media of different time, plotting single phase permeability curve and oil–water two phase relative permeability curve, and analyzing the impact of the value of π on oil–water two phase flow. The results manifest a flow rate difference in pore throat region. The increase of water saturation, the relative permeability of oil phase decreases. However, the relative permeability of water phase increases. Both water phase relative permeability and oil phase relative permeability increase with the decrease of the value of π. The increased value of oil phase relative permeability is greater than that of water phase. As the result, the oil recovery can be enhanced by improving the driving pressure gradient or reducing the interfacial tension.