The oxidative dehydrogenation of ethane into ethylene by carbon dioxide over an unsupported Cr2O3 and several supported Cr2O3 catalysts on metal oxides such as Al2O3, SiO2, TiO2, and ZrO2 was investigated and the effect of support on the catalytic activity was studied. The unsupported Cr2O3 shows medium catalytic activity in this reaction; the support will exert a quite different effect on catalytic behavior. The catalytic activity varies with the nature of supports. Cr2O3/SiO2 catalysts exhibit an excellent performance in this reaction. Cr2O3 loading also affects the catalytic activity; 8 wt.% Cr2O3/SiO2 catalysts can produce 55.5% ethylene yield at 61% ethane conversion at 650 degrees C. Characterization indicates that the distribution of chromium oxide on supports and surface chromium species structure are influenced by the nature of supports. The acidity/basicity and redox property of catalysts determines the catalytic activity in the dehydrogenation of ethane by carbon dioxide.