The equivalent circuit model of the metal oxide anodes used in seawater electrolysis can be described by LRs (QdlRct) (QfRf). The L shows the complex microstructure of the electrode. The (QdlRct) describes the electrochemical behavior of the electrode/solution. The (QfRf) the physical impedance of the Ti-support/active oxide coating. Qdl and Rct do not change sharply in de-active region, but Qf and Rf change abruptly in this region. There are still some active components existing in the surface of the anode. The main reason for the deactivation of the anode is the formation of TiO2 between Ti base and the active coating. The dissolution of the active components and the mechanical lose are not the main reasons for the deactivation of the anodes, but they accelerate the formation of TiO2.