Polymer Electrolyte Membrane Fuel Cells (PEMFCs) has been drown much attentions due to its high energy density, pollution-free electricity generation. Because of its versatile advantages, PEMFCs are considered as next-generation transportation system, which is used for power system of fuel cell electronic vehicle (FCEV). However, the usage of Pt catalyst hinders the widespread application of PEMFC because of high price of Pt. In order to utilize Pt in cost-effective way, various researches have been conducted to maximize the performance and long-term stability of Pt catalyst. Recently, many researches of Pt-metal oxide/C catalyst in PEMFCs have been investigated due to improvement of adsorption characteristics for oxygen at the surface of Pt by adding metal oxide. Especially, Cerium oxide has superior oxygen storage capability originated from easy redox between Ce³⁺ and Ce⁴⁺. Also, Pt-CeO_x interact regions increase active sites where oxygen and Pt catalyst could meet together. In this study, we treated PEMFC cathode by cerium oxide with infiltration process, which enables uniform distribution of added materials with cost-effective way. We investigated the performance of PEMFC membrane-electrode assembly (MEA) with cerium oxide treated cathode. PEMFC performance was evaluated by current-voltage measurement and cyclic voltammetry. Also, the long term stability of cerium oxide treated PEMFC MEA has been analyzed with electrocatalyst accelerated degradation protocol proposed by Department of Energy (DOE). In brief, performance and long term stability enhancement of PEMFC MEA has been observed in cerium oxide treated samples. In our presentation, detail process of experiment and PEMFC performance analysis will be introduced.