To further promote the FO performance of QSTFI membrane, polyvinyl alcohol (PVA) modified QSTFI membrane (PVA-QSTFI) has been developed. The characterization results indicated that the incorporation of a small amount of PVA onto the QSTFI membrane has significant influence on the surface hydrophilicity, pore structure, surface charge and thus FO performance. An optimum PVA loading rate of 0.5% was chosen based on the water flux and specific salt flux experiments. Using the 2.0 molL-1 NaCl as DS, deionized water as FS, the modified membrane offered a 67.08 Lm-2h-1 water flux at 25 ℃, was 12% higher than that of QSTFI membrane. Meanwhile, a specific salt flux of 0.15 gL-1 was obtained, which is 16.7% lower than QSTFI membrane.