Abstract: Further improving the activity and stability of Pt catalysts for oxygen reduction reaction (ORR) is the key to promote the commercialization of proton exchange membrane fuel cells (PEMFCs). In this paper, porous carbon nanofibers (PCNF) with a diameter of about 200 nm were prepared by electrospinning and followed carbonization, which were mixed with carbon black (CB) as a hybrid support for Pt catalysts, and the catalysts Pt/PCNF-CB were prepared by means of ethylene glycol reduction method. The electrocatalytic activity and stability of Pt/PCNF-CB for ORR was investigated by comparing it with commercial Pt/C. When the CB content in the support was 40%, PCNF and CB could disperse uniformly to construct a unique three-dimensional through structure, and the Pt/PCNF-CB-40 prepared from this hybrid support shows excellent ORR electrocatalytic activity in acidic electrolyte with higher onset potential (0.975 V) and half-wave potential (0.781 V) compared with commercial Pt/C. Meanwhile, the Pt/PCNF-CB-40-based membrane electrode assembly (MEA) exhibits higher output performance with a peak power density of up to 599 mW·cm⁻² at low Pt loading, which is a 19% improvement over the commercial Pt/C, and the maximum power density is only lost by 21% after 30 k of accelerated stress test (AST) (0.6 V-0.95 V), compared with the loss of the commercial Pt/C by 41%, demonstrating that the hybrid support formed by PCNF and CB has a positive effect on improving electrocatalytic activity and stability.