The study of the microstructure and electrochemical property of palladium-loaded tantalum oxide (Pd/Ta2O5) particles is presented. Pd/Ta2O5 belongs to the orthorhombic phase. The palladium states onto the Pd/Ta2O5 surface are Pd-0 and Pd2+ forms. From the morphology and size analysis of the loaded Pd particles using transmission electron microscopy, one can see that the nanosized-Pd particles are loaded onto the Ta2O5 surface. A Pd/Ta2O5 film-modified Pt (Pd/Ta2O5-Pt) electrode further exhibits excellent catalytic activity toward electro-oxidation of ethylene glycol (EG) in acid conditions. Density functional theory was also utilized to clarify the effect on microstructure of Ta2O5 after Pd loading showing that the density of states is increased and the density of electrons in the loading region is enlarged after Ta2O5 is loaded with Pd. Therefore, Pd loading improves the conductivity and electrochemical property of the Pd/Ta2O5-Pt electrode.