Polymer electrode membrane fuel cells (PEMFC) are a major obstacle to commercialization due to durability problems caused by corrosion of the carbon support that occurs under special conditions such as start-up and shut-down. Under these conditions, the PEMFC cell voltage generates 1.3 V or more, which accelerate the corrosion of the support in the catalyst layer. In many research groups reported as a main cause of performance decrease and durability reduction by carbon support corrosion. First, the carbon support surface is oxidized and the flooding phenomenon. Second, platinum is removed due to support deterioration. Third, the pores size changes in the catalyst layer. However, these main causes do not explain precisely the cause of the performance drop and increase oxygen diffusion resistance in the mass transport area during carbon support corrosion. In this study, we investigate the causes of the increase of the oxygen diffusion resistance and the decrease of the performance during the corrosion of the support from the viewpoint of the ionomer binder, which is one of the compositions of the catalyst layer, in addition to the cause of the durability drop. Then, various methods have been sought to minimize the degradation of the ionomer during electrode degradation. The ionomer is a polymer and has a motion under high temperature and high humidity conditions. Therefore, the ionomer on the support surface is rearranged during the corrosion of the support. In order to minimize ionomer rearrangement using strong corrosion resistance material CNT is added as a sub-support to overcome the limitation of PEMFC durability, observed that there was little change in oxygen transfer resistance generated during electrode degradation.