Generally, The ion exchange membrane, which is a component of VRFB, is important not only for its excellent chemical stability, but also for its excellent electrochemical properties. In this study, we synthesized four cation exchange membrane of multi-block types with different hydrophobic structures based on sulfonated poly(p-phenylene)s in order to investigate the hydrophobic structure which affects durability in VRFB. In addition, among them, we found one hydrophobic structure suitable for VRFB. And to conclude, Its suitable materials demonstrated excellent oxidation stability, outstanding efficiency performance and low vanadium ions permeability through long-term operation of VRFB.