In　this　study,　a　high-flux　organic　solvent　nanofiltration　(OSN)　membrane　with　the　permeance　of　66.7　Lm(-2)　h(-1)　bar(-1)　in　methanol　and　38.0　Lm(-2)　h(-1)　bar(-1)　in　ethanol　was　successfully　prepared　from　nanoporous　PAN　by　phase　inversion　and　hydrolyzation　in　sodium　hydroxide　solution.　The　polymer　concentration　and　hydrolysis　time　were　varied　to　control　the　final　morphology　and　performance.　The　ternary　phase　diagram　and　viscosity　measurements　were　used　to　describe　precipitation　thermodynamics　and　kinetics　of　the　phase　inversion　process.　The　prepared　membranes　had　a　typical　asymmetric　structure,　which　could　be　observed　from　images　of　the　cross　section,　comprising　a　dense　skin　layer　and　a　porous　substructure　in　the　sublayer.　It　was　found　that　the　polymer　concentration　has　an　apparent　influence　on　the　morphology,　selectivity　and　permeability　of　the　prepared　membranes.　FTIR　analysis,　zeta-potential　and　water　contact　angle　measurements　confirm　a　molecular　chain　rearrangement　as　hydrogen　bonds　were　formed　between　CONH2　and　COOH　groups　during　the　carboxyl　modification　process.　Moreover,　an　increase　of　the　surface　hydrophilicity　was　obtained　by　hydrolysis.　A　good　solvent　resistance　and　a　satisfactory　separation　performance　in　the　nanofiltration　range　were　achieved　with　hydrolyzed　PAN　membranes　in　polar　as　well　as　nonpolar　solvents.　The　relationship　between　solvent　permeation　and　combined　solvent　properties　(viscosity,　molar　diameter　and　solubility　parameter)　indicated　a　strong　interaction　of　selected　solvents　with　polymers　except　alkanes.　The　hydrolyzed　PAN　membrane　was　applied　to　fractionation　of　dyes　and　Na2SO4　solution　compared　to　commercial　NF　membrane.　The　high　dye　rejection　and　salt　permeance　remained　constant　with　the　salt　addition　for　high　flux　hydrolyzed　PAN　showing　the　fractionation　potential　for　dyes　and　divalent　salts,　and　establishing　the　strong　advantage　over　commercial　NF　membranes.