Abstract: The equations with coupled boundary condition on the interface, which govern the process of pressured pore water infiltration and pore gas flow in unsaturated soils, are established in this paper based on the equilibrium analysis for pore water and pore gas separately. The experiments on the water infiltration in dry sands in one-dimensional channel show the influence of pore gas flowing on the water infiltration process. The numerical solution of the process and comparison of the results between the numerical simulation and the experiment are also proposed.