A series of binary RuO2-Ta2O5 oxide composites with different Ru/Ta molar ratios were deposited on titanium substrate by a thermal decomposition method. The structure, voltametrical characteristics and capacitive properties as a function of the Ru/Ta molar ratios were investigated by X-ray diffraction (XRD), cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The results show that the degree of crystallization of the Ti/RuO2-Ta2O5 electrodes decreases with the increase of Ta2O5 content in the RuO2-Ta2O5 oxide coatings. A completely amorphous structure exists as the proportion of Ta2O5 is up to 70 mol% or higher. The electrochemical performance of the Ti/RuO2-Ta2O5 electrodes is closely related with the composition and structure. The specific capacitance increases firstly and then decreases with the ratio of Ta to Ru in oxide coatings, and a maximum specific capacitance of 621.2 F·g-1(RuO2) is obtained when the Ta2O5 content is 70 mol%.