The Rn-Ir-Sn metal oxide anodes coated on titanium were prepared by thermal decomposition. The anodes were studied by SEM, EDX, cyclic voltammetry, electrochemical impedance spectroscopy and accelerated life test, which characterized the deactivation behavior of metal oxide anode electrolyzing at different temperatures of seawater. The results indicate that the center of the deactivated anodes electrolysed at 5~20 °C has traces of the coating with remained dried-mud cracks while the bare Ti substrate is exposed in the surrounding area at the edge, which os caused by the dissolution of the active components, and the peeling of the coating. When the electrolysis temperature of seawater is 40 °C, the service life of the anode is longer, the uniform electrochemical dissolution of the anode coating takes place. In addition, the electrochemically active surface area and the stability of the anode increase with the rising of the temperature. The deactivation of the anode at 5~20 °C is attributed to the selective dissolution of Ru and the partial detachment of the coating, and the deactivation of the anode at 40 °C is ascribed to the formation of TiO2 between Ti base and the active coating