In the present work acid-treated Ni catalyst was investigated for the steam reforming (SR) of bio-ethanol. Influential factors, such as reaction temperature, water-to-ethanol molar ratio and liquid hourly space velocity (LHSV), were investigated. The conversions were always complete at temperatures above 773 K, regardless of the changes of the reaction conditions. The yield to hydrogen increased with the increase in temperature and H2O/C2H5OH molar ratios. The hydrogen yield up to 84% was reached under conditions: 923 K, LHSV of 5.0 ml g(-1) h(-1), H2O/C2H5OH ratio of 10 over the acid-treated Ni catalyst. The effects of the influential factors on the side reactions and the distribution of byproducts were discussed. Copyright (C) 2010 John Wiley & Sons, Ltd.