IrO2-Ta2O5　binary　oxide　coatings　were　prepared　on　Ti　substrate　by　thermal　decomposition.　The　influence　of　annealing　temperature　on　the　structure　and　capacitive　performance　was　investigated　by　means　of　X-ray　diffraction　(XRD),　cyclic　voltammetry　(CV),　galvanostatic　charge/discharge　and　electrochemical　impedance　spectroscopy　(EIS),　and　the　structure-performance　relationship　was　discussed.　The　results　show　that　the　phase　of　the　coating　annealed　at　<　350　℃　still　remains　amorphous.　When　annealing　at　370　℃,　the　rutile　phase　appears　and　the　coatings　contain　both　crystalline　and　amorphous　structures.　The　critical　crystallization　temperature　of　the　IrO2-Ta2O5　is　between　350　and　370　℃.　The　specific　capacitance　of　the　IrO2-Ta2O5　increases　with　the　increasing　temperature　up　to　370　℃,　and　then　decreases　with　further　increasing　temperature.　The　electrodes　annealed　at　370　℃　have　the　largest　integral　power,　the　minimum　loss　rate　of　electricity　and　the　highest　specific　capacitance　of　239.2　F/g.　With　the　increasing　annealing　temperature,　the　charge　transfer　resistance　Rct　decreases.　©　2017,　Editorial　Office　of　Transactions　of　Materials　and　Heat　Treatment.　All　right　reserved.