Hydrophilic modification of polyethersulfone (PES) membranes was achieved by blending Pluronic polymers with different contents and PEO chain length. The static water contact angle measurements and X-ray photoelectron spectroscopy analysis confirmed the enrichment of PEO chain at blend membranes surface. Effect of Pluronic polymer content and PEO chain length on ultrafiltration performance and fouling-resistant ability of blend membranes was studied. The results indicated that except for PES-P 123 blend membranes, the water fluxes of blend membranes were higher than that of PES control membrane. Meanwhile, increasing Pluronic content or PEO chain length both improved the fouling-resistant ability of blend membranes significantly. Finally, the outstanding flux recovery property of blend membranes ensured the long-run utilization time and operation reliability. (c) 2006 Elsevier B.V. All rights reserved.