In this study, Co-N-C supported on silica spheres is prepared through heat-treatment of supported metalloporphyrin in an N2 atmosphere. The catalytic performance of the catalysts for ethylbenzene oxidation is investigated and these catalysts are characterized by techniques such as BET, FT-IR, UV-vis, TEM and XPS. In comparison with other catalysts such as supported cobalt porphyrin and unsupported cobalt porphyrin, Co-N-C supported on silica spheres shows much higher catalytic activity for ethylbenzene oxidation (15.7%) and selectivity to acetophenone (76.5%). In addition, the catalyst can retain its high catalytic activity after several reuses. The results show that the high catalytic performance of the catalyst may be attributed to the formation of Co-N4-C sites during the heat-treatment and supported Co-N-C catalysts may be beneficial to yield more Co-N4-C sites.