Perovskite LaCoO3 and perovskite-like LaSrCoO4 mixed oxides were prepared by polyglycol gel method, and their catalytic performance was compared for the selective oxidation of hydrogen sulfide in a stream containing excess amount of ammonia and water for the first time. These samples were investigated by using XRD, BET, O2-TPD and XPS. The catalytic activity and the selectivity to solid products (ammonium thiosulfate and elemental sulfur) of LaCoO3 were better than those of LaSrCoO4, and this is explained in terms surface contents of oxygen and cobalt, oxidation state of cobalt, and BET surface area.