The process of melt infiltration of WCu alloy was simulated by the finite element software. A spherical particle skeleton model was established according to the distributing morphology of W particles. The pressure and the velocity vector distribution of copper liquid in the flow path were analyzed in isodiametric and non-isodiametric porous system. The relationship between the depth and time of infiltration in the porous system is obtained when the average particle size of W powder is 5 μm, which is in good agreement with experimental values