In the present study, novel pervaporation (nonporous, dense) and ultrafiltration (porous) membranes based on polyphenylene isophthalamide (PA) modified by Pluronic F127 (up to 20 wt%) used as a modifier and a pore-forming agent were developed and investigated. The structural parameters of the membranes obtained were studied by IR-spectroscopy, nuclear magnetic resonance, scanning electron microscopy, sorption experiments, porosimetry, and contact angle measurements. The transport properties of the dense membranes were analyzed in separation of azeotropic methanol/toluene (72/28 wt%) mixture by pervaporation, while the porous membranes were examined in ultrafiltration of pure water and bovine serum albumin (BSA) solution. It was found that the optimum Pluronic F127 content for the pervaporation membranes was 10 wt% as it led to the 2 times increase of normalized flux and to the rise of methanol content in the permeate by 5 wt%. For the ultrafiltration membranes, the addition of up to 20 wt% Pluronic F127 into the PA matrix provided 2 times increased water flux, preserving good antifouling resistance. The improved transport characteristics of the developed membranes were related to the significant changes of the structural and physicochemical properties of the PA membranes modified by Pluronic F127.