Pt nanoparticle-loaded carbon nanohorns (Pt/CNHs) nanocomposites were synthesized by using formic acid as reducing agent at room temperature. Taking the advantage of the high surface area and excellent electronic conductivity, CNHs were used as support without any pretreatments for the enhancement of catalytic performance. By adjusting the feeding amount of H2PtCl6, the mass, size and distribution of Pt nanoparticles could be effectively controlled on CNHs. Compared with commercial Pt/C, the synthesized Pt/CNHs exhibit higher catalytic activity and improved long-term stability toward both methanol and formic acid oxidations. Among the Pt/CNHs, 13% wt. Pt/CNHs exhibit the best catalytic performances for the small size (2.4 nm) and uniform distribution of Pt NPs on CNHs. Our work reveals the superior catalytic performance of Pt/CNHs which may be a promising substitute for commercial Pt/C. (C) 2017 Published by Elsevier Inc.