Abstract: Ti/IrO2-Ta2O5 electrodes were prepared by low thermal decomposition method. The influence of Ta contents on the microstructure and capacitive performance of the Ti/IrO2-Ta2O5 electrodes was investigated by XRD, cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge-discharge tests. The results showed that Ta2O5 can inhibit crystallization of the IrO2.With increasing Ta contents, the crystallization degree decreased.When the content of Ta increased to 60%mol, the electrode with a content of 6.4% crystalline structure had a superior capacitive performanceof 239.2 g/F,which was considerably higher than that of IrO2 electrode(54.1 g/F) .