Objective To facilitate the commercialization of proton exchange membrane fuel cells by revolving the key issues including low utilization and deteriorated stability of noble metal catalysts. Methods After preparation of PtCo alloy catalysts with low Pt loading by a chemical co-deposition method, the gold decorated PtCo alloy catalyst was prepared in terms of an under-potential-deposition method, and then the electrochemical stability of the gold-decorated PtCo alloy catalyst was characterized by atomic absorption spectroscopy and electrochemical accelerated test technique. Results Au-decorated PtCo alloy catalyst was successfully prepared. After decoration of gold, the oxygen reduction reaction activity of PtCo alloy catalysts remained unchanged, and the erosion rate of Co element for PtCo alloy catalysts in electrolyte solutions decreased with an improved electrochemical stability. Conclusion It was feasible to improve the stability of PtCo alloy catalysts by decoration with metals possessing a high corrosion potential such as Au.