The room temperature wet catalytic oxidation was conducted in a batch reactor with Fe/MgO catalyst. Fe/MgO catalyst was prepared by the dissolution-precipitation method. XRD and temperature-programmed reductions (TPR) indicate that Fe oxide in the Fe/MgO is finely dispersed in the MgO support. The high H2S removal capacities of Fe/MgO can be explained by the finely dispersed iron oxide MgO. The H2S removal capacities of Fe/MgO are dependent on oxygen partial pressure (1.0 g H2S/g(cat) in air and 2.6g H2S/g(cat) in oxygen). The valence state analysis of Fe/MgO catalyst suggests that the H2S oxidation on Fe/MgO can occur by a redox couple reaction, reducing Fe3+ into Fe2+ by H2S and oxidizing Fe2+ to Fe3+ by O-2.