Onion-like Fullerenes (OLFs) were prepared by CVD method and purified by nitric acid treatment. Pt/OLFs catalyst was prepared by the impregnation-reduction method with three different loadings of formaldehyde as the reductive, and the morphology and structure were characterized. XRD patterns showed that excess of the reductive benefited the growth of Pt crystals. HRTEM images showed that Pt particles with the diameter of 2.5–3.5 nm were distributed well in the Pt/OLFs catalyst. FT-IR spectrum also indicated that several functional groups existed on the surface of purified OLFs. TG pattern showed the high supporting rate of Pt. The results showed that formaldehyde exhibited reducing activity during the growth of Pt/OLFs.