Well-dispersed trimetallic-alloyed PdSnCo nanocrystals with an average size of 7nm are supported on nitrogen-doped reduced graphene (NG) nanosheets by a solvothermal method. The PdSnCo/NG nanocatalyst is characterized by scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. As a result, the PdSnCo/NG exhibits high catalytic activity toward oxygen reduction reaction and high electrochemical stability in alkaline medium, compared to commercial 10% Pd black, binary PdSn/NG, and PdCo/NG. Moreover, PdSnCo/NG nanocatalyst shows high discharge capacity of 6750mAhg−1, low charge voltage and predominant cycleability for lithium-air batteries.