REO-ZrO2 mixed oxides serve as a key material in the electrolyte of oxygen sensor and promoter of three-way catalyst (TWC), which are widely applied in the purification of automotive exhaust. The principles of the applications were expounded; meanwhile the adulteration of RE ions into ZrO2 applied in oxygen sensor was introduced. The research of CeO2-ZrO2 mixed oxides applied as promoter of TWC was summarized, and the further application of REO-ZrO2 composite in the automotive exhaust decontamination was prospected.