Bio-ethanol is a renewable energy carrier and its use in the reforming of bio-ethanol is promising for hydrogen production. In this work, a set of materials containing mixtures of Co3O4/CeO2 (5, 10 and 20% Cowt.%) were synthesized by one-step polymerization method (OSP method), and were tested in ethanol steam reforming (SRE). For comparison purposes, the best catalyst of this set was compared with a similar one synthesized by the impregnation method. The XRD, SEM and TPR analyses of the CoCe catalysts prepared by the OSP method showed that the increase of the cobalt content increases CoOCe interaction, this interaction had positive effects on the catalysis of SRE. The OSP method provides a more homogeneous material leading to finely dispersed metallic cobalt which favored the catalysis of the SRE at 500°C; the best catalyst was the Co3O4/CeO2 mixture with cobalt content of 20 wt.% (20CoCe catalyst). This catalyst reported high metallic dispersion, high-surface-area, high selectivity to H2, good catalytic stability and low carbon deposition rate. This catalyst is promising for the steamreforming of bio-ethanol. The catalyst prepared by the impregnation methodwas not good for the catalysis of SRE at 500°C.