Abstract: Composite CeO₂-Al₂O₃ oxides with high surface area, large pore volume and large pore diameter were prepared by ultrasonic co-precipitation; with CeO₂-Al₂O₃ as the support, Pt/CeO₂-Al₂O₃ catalysts were obtained by impregnation method. The supporter and the as-prepared Pt/CeO₂-Al₂O₃ catalysts were characterized by XRD, NH₃-TPD, nitrogen sorption and SEM; their catalytic performance in the dehydrogenation of methylcyclohexane as a model compound was investigated in a micro tube-reactor and the influences of Ce/Al (mol ratio) and reaction temperature on the dehydrogenation activity were considered. The results indicate that the Pt/CeO₂-Al₂O₃ catalyst with a Ce/Al (mol ratio) of 0.5 performs best at 450℃ in the dehydrogenation of methylcyclohexane, with a methylcyclohexane conversion of 88.53% and a selectivity of 94.63% to toluene.