Small-sized and well-dispersed Pt-Au nanoparticles (Pt-AuNPs) grown on carbon nanofibers (Pt-AuNPs/CNFs) with excellent electroanalytical and electrocatalytic performance in the detection of H2O2 and the catalytic hydrogen evolution reaction (HER) were designed and fabricated via electrospinning technology and an in situ thermal reduction process. Large numbers of Pt-AuNPs were homogenously distributed on the CNFs. A Pt-AuNP/CNF hybrid with low Pt content was utilized as a bifunctional electrocatalyst, exhibiting a higher response current of 116 mu A without an enzyme in the detection of H2O2 and a lower overpotential (j = 10 mA cm(-2) at -235 mV) and Tafel slope (84 mV decade(-1)) for HER than the PtNPs/CNFs and the AuNPs/CNFs. These results were ascribed to the specific nanostructure of the well-dispersed Pt-AuNPs, the favorable electron transport capability, the excellent durability of the CNFs, and the enhanced surface-specific area of the Pt-AuNPs/CNFs. This study offers a green and facile method for constructing a specific bimetallic nanostructure for application in catalytic fields.