Polypropylene (PP) is one of the most used polymers for microporous membrane fabrication due to its good thermal stability, chemical resistance, mechanical strength, and low cost. However, the hydrophobic nature of PP membrane greatly limits its application, e.g., being susceptible to fouling when applied in an aqueous application, and suffering from wetting when used as battery separator or membrane contactor. To address these issues, numerous efforts have been devoted to the hydrophilic modification of PP membrane. In this work, a novel amphiphilic molecule, 1,3:2,4-Di(3,4-dimethylbenzylidene) sorbitol (DMDBS), was added into PP during extrusion of the cast films. By regulating the processing conditions, DMDBS can migrate onto the film surface and assemble into the nanofibers network as observed by SEM. The precursor films were fabricated into the microporous membranes according to the common dry stretching strategy same as that of the pristine PP film. Water vapor transmission rate (WVTR) measurements show the WVTR value gets improved as the polarity of DMDBS facilitates the adhesion of the water vapor molecules with the membrane. Consistently, reduced water contact angle can be observed for the PP/DMDBS membrane, compared to that of the neat PP membrane.