The activity of catalysts before and after heat treatment up to 950 degrees C was measured in model reactions of methane and butane deep oxidation. The poison stability was investigated by examining the catalysts in deep oxidation of methane (1 vol% in air) in the presence of SO2 (0.05 vol%). The alumina-manganese oxide catalyst was found to be the most resistant to overheating, It lowered the activity in deep methane oxidation similar to 2.5 times only after calcination at 950 degrees C for 800 h. The more poison stable samples were found to be alumina-palladium and perovskite (on the base of LaMnO3) catalysts, The activity of more thermostable alumina-manganese oxide catalyst is lowered up to zero activity in deep oxidation of methane at 500 degrees C. But at reaction temperature 700 degrees C the catalyst is sufficiently stable to poisoning.