Bimetallic PtPd alloys are regarded as promising high performance oxygen reduction reaction (ORR) catalysts. However, the application of a subnanometer scale PtPd bimetallic nanoclusters (NCs) is rarely studied. In this work, ordered mesoporous carbon (OMC) supported PtPd NCs with the constant metal loading of 10 wt% and various Pt:Pd atomic ratios were synthesized by a modified polyol reduction route. The PtPd NCs show a maximum activity at Pt:Pd molar ratio close to 3:1 with a mean size of similar to 2.35 nm. The specific activity (SA) and mass activity (MA) of Pt3Pd1 NCs/OMC (PtPd loading: 10 wt %) is 2.5 and 4.1 times higher than those of the commercial PVC (Pt loading: 20 wt%) in 0.1 M HClO4. Meanwhile, the Pt3Pd1 NCs/OMC exhibits improved methanol tolerance and durability for ORR. Therefore, the Pt3Pd1 NCs/OMC is excellent candidate that may become a practical cathode catalyst for fuel cells.