Recently, proton exchange membrane(PEM) fuel cells have been widely considered as one of alternative devices for energy generation system as a clean and efficient for transportation and many other applications. The PEMFC systems need functionalized polymer as PEM which can transfer protons. The PEM for PEMFC require high proton conductivity, good chemical and mechanical durability. In particular, physical and chemical durability of PEM is important because the operation condition of the fuel cell for automobile needs to be repeatedly humidified and dried and requires high output. We so have introduced a porous substrate into the PEM to prepare reinforced polymer electrolyte membrane that it can stand severe condition. The reinforced PEM has good mechanical stability like dimensional stability and water uptake because the porous support suppresses the volume expansion in the plane direction. So reinforced PEM exhibits enhancement of physical properties and durability than freestanding PEM, but its overall characteristics and performance are affected by the structure of the composite layer. Therefore, in this study, we tried to derive the optimum combination condition of ionomer and support. The results obtained from this study show that the reinforced PEM can ensure physical durability through dimensional stability and its properties depend on the structure of the composite region and the substantial porosity of the substrate.