The enhancement of electrocatalytic activity of carbon-supported platinum catalysts has been essential for improving the performance of proton exchange membrane fuel cells (PEMFCs). In this paper, one kind of grounded ultrafine porous carbon fiber (UPCF), with an average diameter of the order of 100 nm and pore sizes of 5-30 nm, was used as a novel compound carbon support (CCS) to prepare a supported Pt catalyst (Pt/CCS) for the electrode catalyst layer in a PEMFC, and its associated membrane electrode assembly (MEA). The fabricated MEA was also tested in a single fuel cell to validate this Pt/CCS catalyst. The electrochemical surface area (ECSA) of Pt was determined to be 71.9 m(2).g(-1) for the CCS, which is much larger than the 54.6 m(2).g(-1) known to apply for carbon black support. Both the onset potential and half-wave potential of Pt/CCS were all positively shifted in comparison with Pt/C, based on linear sweep voltammetry (LSV). The performance of a single fuel cell catalyzed by Pt/CCS showed 1.25 times higher power density than that catalyzed by Pt/C at room temperature. The cross-sectional morphology of the electrode indicated the chopped-fiber-form UPCF might construct a loose three-dimensionally layer-like catalyst that could reduce mass transform resistance and allow the water produced to escape easily. (C) 2015 Elsevier Ltd. All rights reserved.