Abstract: The structure change and failure behavior of Ti/SnO₂+Sb₂O₃/PbO₂ anodes were studied during the electrolysis process in 1.0 mol•L^-1 H₂SO₄ solution.The morphology，microstructure and the electrochemical behavior of the anodes in the different electrolysis processes were examined by means of XRD，SEM，CV and EIS.The variation of cell potential went through three stages：“instability”，“stability”and“rapid rising”in the whole electrolysis process.The morphology，microstructure and the electrochemical behavior of the anodes changed obviously in these stages.In the later stage of the electrolysis process，the passivation film of TiO₂ between the Ti substrate and the oxide coating was formed and PbO₂ coating peeled from the electrode，which caused the inactivation of electrodes.