NaY-zeolite was employed as a support of ruthenium catalysts for aqueous phase reforming of acetic acid. Catalytic activities of the supported ruthenium species on NaY-zeolite depended on oxidation state controlled by preparation conditions. Catalyst NaY(exc), whose 5 wt% ruthenium precursors were supported through cation-exchanging process, produced H-2 continuously for 10 h when the catalysts were used without reducing by H-2 prior to usage. Decreasing the loading amounts of ruthenium on NaY(exc) led to improve the selectivity toward complete reforming of acetic acid giving H-2 and CO2 because of the strong interaction between positively charged ruthenium particle and the support. However, contents of sodium cations controlled by the pH of precursor solutions did not affect the catalytic performances. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.