The water-gas shift reaction (WGSR) has been studied on Au/alpha-Fe2O3 catalyst. The structure of the samples has been investigated by chemical and physical methods - TEM, X-ray, DTA, FTIR. A high dispersion degree of the gold particles and an increased concentration of the hydroxyl groups on Au/alpha-Fe2O3 has been established in comparison to the pure alpha-Fe2O. The results obtained can be explained on the basis of the associative mechanism of the WGSR. The essential aspects are the dissociative adsorption of water on ultrafine gold particles, followed by spillover of active hydroxyl groups onto adjacent sites of the ferric oxide. The formation and decomposition of intermediate species is accompanied by redox transfer Fe3+ <-> Fe2+ in Fe3O4.