In this study, the ternary catalysts in a form of Pd75Co 25-xAux/C (x = 5, 15 and 25 in at.%) are synthesized for the oxygen reduction reaction (ORR) through the deposition-precipitation method. The addition of Au in altering structures, surface conditions and electrochemical properties of PdCo catalysts are investigated by the combined exploration of XRD, TEM, cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurements. XRD results suggest that the incorporation of Au into Pd-Co contributes to the formation of inhomogeneous alloy structure. Regarding the surface condition, CV examination implies that the Pd-rich surface gradually changes to Pd, PdAu or PdCo alloy mixed surface species after Au modification. For the preparation of high effectively catalysts, it is suggested that the addition of Au can prominently promote the ORR activity owing to the presence of inhomogeneous alloys together with alloy mixed surface species.