A cross-linked sulfonated polyethersulfone supported Ru nanoparticle catalyst was prepared for highly hydrogenation of levulinic acid (LA) into,gamma-valerolactone (GVL) at mild conditions (3.0 MPa H-2 and 70 degrees C) in aqueous solution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterizations show the formation of highly dispersed small (similar to 3 nm) Ru clusters on the surface of polyethersulfone. Infrared spectroscopy (IR) and acid-base titration indicate the presence of sulfonic groups without the influence of the deposition of Ru species. Polyethersulfone consisted of cross-linked electron - withdrawing group -SO2-, maintained its intrinsic thermal stability during the hydrogenating reaction process, and its swelling property promoted the adsorption of LA in aqueous solution. The synchronization of sulfonic groups as active sites for esterification process and metal sites for hydrogenation promoted the hydrogenation reactivity. (C) 2014 Elsevier B.V. All rights reserved.