In this paper TiN coating as an interlayer was fabricated on Q235 steel substrate by reactive plasma spray method and its microstructure and influences on the performance of the Fe/TiN/PO2 electrode were investigated. It is shown that the TiN coating has a rough surface and layered cross-section structure. The coating consists of main TiN phase and a small quantity of Ti oxides. After heat-treated below 550°C the TiN coating is greatly densified due to the increase of Ti oxides, and however the electric resistance of the Fe/TiN samples is still lower than that of the Ti substrate. For the Fe/TiN/PbO2 electrode a rougher surface and more micropores were observed in the active PbO2 coating than on the surface of the Ti/PbO2 electrode. Due to the presence of the TiN interlayer the Fe/TiN/PbO2 electrode shows an accelerated life of 180h under the test condition, which is much longer than 28min of the Ti/PbO2 electrode.