The room temperature wet catalytic oxidation was conducted in a batch reactor with V/MgO catalyst. The XRD study of the catalyst used indicated that V/MgO could not only oxidize H2S to sulfur selectively, but also prevent the sulfidation of metal oxide effectively at room temperature. The XPS study indicated that the H2S oxidation with V/MgO could proceed by a redox mechanism (V5+ <----> V4+) and that V3+ formation (V4+--> V3+), was responsible for the deactivation of V/MgO.