Ordered mesoporous structures were successfully introduced into Nafion membranes via a soft micelle templating method, using a nonionic block copolymer surfactant, PEO127-PPO48-PEO127 (Pluronic F108). The mesoporous Nafion or meso-Nafion membranes were characterized by the AFM, SAXS, TGA and conductivity measurements. The results show that the meso-Nafion has a very high water retention capability. The proton conductivities of meso-Nafion are also much higher than that of Nafion 115 membranes particularly at reduced relative humidity (RH) and elevated temperatures. At 80˚C and 40%RH, the conductivity of meso-Nafion is 0.07 Scm-1, more than 3 times better than Nafion 115. At 60%RH and 80˚C, the cell with meso-Nafion reached a stable power output of 0.63 Wcm-2, more than 2 times higher than the cell with pristine Nafion 115 under identical experimental conditions. The cells with meso-Nafion membrane also demonstrate much better stability at elevated temperature of 120˚C and reduced humidities.