The correlation of the porosity and the permeability, based on the experimental data, for the TGFM-300 P/E random fiber mat is proposed in the present work. The edge effect is simulated by the creeping motion of the resin with permeable boundary condition along the edge of the fiber mats. Results show that the edge effect is very sensitive to the shape of the fiber mat. Numerical predictions agree with experimental results, when the fiber mat is well shaped. The edge effect is negligible as the dimension of the fiber mat is slightly larger than that of the mold cavity. The present paper combines the body-fitted FDM and the FEM to deduce an auto-meshed and auto-node-element relating numerical scheme. This scheme is convenient and effective in solving the moving boundary problems with irregularly geometric boundaries, such as the filling process of RTM. The difference between the elliptic type body-fitted FDM and the FEM are compared and discussed in detail.