Pt nanoparticles supported on nitrogen doped carbon (Pt/CN) catalysts with different surface areas were obtained and characterized by transmission electron microscope （TEM） and brunner-emmet-teller （BET）. The characterized results showed that Pt nanoparticles dispersed uniformly on the support surface, and the surface area of the Pt/CN catalyst increased with the increase of annealing temperature. Subsequently, the catalytic performance of Pt/CN catalysts for methylcyclohexane dehydrogenation was studied. The activity of Pt/CN catalysts in methylcyclohexane dehydrogenation increased with the increase of the surface area, Pt/CN-1000 catalyst has the largest surface area and the highest catalytic activity, with the methylcyclohexane conversion of 99% and the TOF value of 424.78 h -1 at 180 ℃ for 150 minutes.