Pt nano particles were synthesized on carbon nanotubes (CNTs) by chemical vapor deposition (CVD). (Trimethyl)methylcyclopentadienyl platinum (MeCpPtMe3) was used as Pt precursor, which was vaporized at 70oC and delivered to the pretreated CNTs at the reactor. The CVD was performed at various temperatures, 80~270oC with various gas flows. Consequently, Pt nano particles of 1~2 nm size were synthesized by CVD, which is much smaller than the Pt particles prepared by wet impregnation and by electrochemical deposition. The surface characterizations of Pt/CNT catalysts were performed by XRD, HR-TEM, CO chemisorption, etc.