A hybrid two-phase three-dimensional and non-isothermal mathematical model was developed for proton exchange membrane fuel cell (PEMFC) with straight channel.The capillary flow and the distribution of liquid water in porous media were considered in this model.And the effects of the structure of two-layer gas diffusion layer (GDL) and the characteristics of carbon fiber on fuel cell performance were analyzed.The results indicated that the thickness of the first layer of GDL

which should be optimized

had contrary effects on the conductivity of membrane and the transport process of gas species.For certain conditions

the decrease of carbon fibers diameter of the first layer of GDL increased the conductivity of membrane

which enhanced the performance of fuel cell.The hydrophobility and porosity of porous media should be increased to improve the cell performance while keeping other parameters constant.