Carbon-supported PtPdRuIr, Pd@PtRuIr, PtPd@PtRuIr, and PtPdRu@PtRuIr catalysts were prepared by a colloidal method and their catalytic activities to the methanol oxidation reaction in the acidic media were extensively investigated at room temperature. The catalysts were characterized by transmission electron microscopy and X-ray diffraction techniques, and their electrochemical behavior was evaluated by the cyclic voltammetry. The PtPdRu@PtRuIr/C catalyst is found to yield much higher electrocatalytic activity than the other ones and the commercial catalyst. For example, the Pt metal mass-specific activity of this PtPdRu@PtRuIr/C(Pt content 10 wt%,1.7 mAácm-2ámg-1) electrocatalyst is *3-fold higher than that of the commercial JM 40 % Pt/C(0.6 mAácm-2ámg-1)electrocatalysts, and the If/Ib ratio of PtPdRu@PtRuIr/C is1.6, which is higher than that of the JM 40 % Pt/C(0.9). The improvement may result from the high dispersion of the active metal catalyst and the synergistic effect between the PtRuIr and PtPdRu layers. It is thus concluded that the pseudo-core–shell structure could significantly improve the methanol electro-oxidation activity and CO tolerance of the electrocatalyst. Carbon-supported PtPdRuIr, Pd @ PtRuIr, PtPd @ PtRuIr, and PtPdRu @ PtRuIr catalysts were prepared by a colloidal method and their catalytic activities to the methanol oxidation reaction in the acidic media were extensively investigated at room temperature. The catalysts were characterized by transmission electron microscopy and X-ray diffraction techniques, and their electrochemical behavior was evaluated by the cyclic voltammetry. The PtPdRu @ PtRuIr / C catalyst is found to yield much higher electrocatalytic activity than the other ones and the commercial catalyst. For example, the Pt metal mass-specific activity of this PtPdRu @ PtRuIr / C (Pt content 10 wt%, 1.7 mA a cm-2 a mg-1) electrocatalyst is * 3-fold higher than that of commercial JM 40% Pt / C ) electrocatalysts, and the If / Ib ratio of PtPdRu @ PtRuIr / C is 1.6, which is higher than that of JM 40% Pt / C (0.9). The improvement may result from the high dispersion of the active metal catalyst and the synergistic effect betwee n the PtRuIr and PtPdRu layers. It is thususted that the pseudo-core-shell structure could significantly significantly improve the methanol electro-oxidation activity and CO tolerance of the electrocatalyst.