IrxOy-SnO2/Ti　electrodes　were　prepared　by　thermal　decomposition　using　H2IrCl6　and　SnCl4　as　precursor　materials　with　the　Ir　to　Sn　mole　ratio　of　4　to　6.　The　effect　of　heat　treatment　temperature　and　holding　time　on　the　phase　composition,　stable　specific　capacitance　and　activation　energy　of　the　electrode　materials　were　characterized　by　XPS　and　cyclic　voltammograms.　The　results　indicate　that　the　materials　are　composed　of　mixed　oxides　of　IrO2,　Ir2O3　and　SnO2.　All　the　inner　charges　are　larger　than　the　outer　charges.　The　inner,　outer　and　total　charges　increase　first　and　then　decrease　with　the　temperature　increasing.　The　highly　stable　electrodes　with　a　total　charge　of　the　max　value　of　513.9　mC·cm-2　and　a　specific　capacitance　of　280　F·g　IrO2-1　are　obtained　at　approximately　320°C.　Even　if　the　electrodes　are　heated　at　360°C,　the　stable　specific　capacitance　exceeds　150　F·g　IrO2-1.　The　annealing　time,　needed　to　obtain　a　stable　IrxOy-SnO2/Ti　electrode　at　various　temperatures,　correlates　well　with　the　Arrhenius＇　law,　the　activation　energy　(E)　of　the　annealing　reactions　for　the　electrodes　is　4.54　kJ/mol.　The　smaller　the　activation　energy　is,　the　smaller　effect　of　holding　time　on　the　specific　capacitance　is.