Polymer electrolyte fuel cell (PEFC) using liquid phosphoric acid (PA) as polymer electrolyte membrane has poor durability due to leaching of PA from the membrane, resulting to the deterioration of PEFC performance during long-term operation. To overcome this issue, poly(vinylphosphonic acid) (PVPA) was used for electrolyte instead of PA. Although this PEFC showed high durability, this catalyst had large overpotential in the area of low current density, probably due to the poisoning of Pt by PVPA. In this study, we studied an effect of ionomer chemical structure for oxygen reduction reaction.