A method for separating sodium alginate through polysulfone (PSf) support by dimethyl acetamide (DMAc) and hydraulic treatment was studied. After exposing the PSf support to DMAc solvent, water pressure was applied onto the polymer support. As a result, the sponge-type structures were connected to each other and the porosity of the modified PSf increased. In addition, the support pressurized for 3minutes at 8 bar had the highest value of 133 L/m2h and removal rate of 95.0% for sodium alginate filtration test. When the PSf support was immersed in an organic solvent, the interaction between the chains of the PSf was weakened, while when water pressure was applied, pores were generated. These results were confirmed by SEM, FT-IR and porosimeter data.