A series of analysis methods is proposed to simulate the liquid gas two-phase and multi-component transport phenomena in the gas diffusion layer (GDL) of a polymer electrolyte fuel cell (PEFC). These methods involve measuring and predicting the two- phase flow properties of a GDL, the capillary pressure and relative permeability, and simulating the two-phase multi- component transport in the GDL. The methods are described and applied to a carbon-fiber paper GDL. The predicted capillary pressure and relative permeability correctly captured the shape of the curve of the measured results and showed the similar magnitude to those. Transport simulation is carried out with the properties to identify in detail the two-phase multi- component transport. Since the fibrous structure and wettability of the GDL are considered, advanced analysis can be conducted with the methods.