Traditional solvents are harmful to human health and the environment. Here, we use a green solvent, dimethyl sulfoxide (DMSO), to replace traditional solvents partly as well as improve membrane performance. The amphiphilic copolymer poly(vinyl chloride)-graft-poly (ethylene glycol) methyl ether methacrylate (PVC-g-PEGMA) is blended with PVC to improve the membrane performance. PVC cannot dissolve in DMSO, so based on the Hansen solubility parameter calculation, we investigated the mixture solvents of traditional solvents and DMSO. We found that membranes fabricated by solvent 1-methyl-2-pyrrolidinone (NMP)/N,N-dimethylacetamide (DMAc)/DMSO = 4/3/3 had the highest pure water flux of 891.54 +/- 64.41 L m(-2) h(-1) bar(-1) and the highest sodium alginate (SA) rejection of 94.7 +/- 1.3%. Other studies have rarely reported modified PVC membranes with such good performance. This membrane was a successful attempt to use a green solvent in membrane fabrication, meeting the challenges of sustainability in chemical enterprises.