The reduction of high-active FeAl and CuFeAl composite catalysts was investigated in situ by XRD and XAS in the temperature range between 100 and 600 °C. It was found that the fresh catalysts consist of Fe2O3 and Al2O3 phases only. The Al3+ cations partially dissolute in the Fe2O3 lattice. The addition of copper to the Fe-Al catalyst leads to formation of highly dispersed CuO nanoparticles and mixed oxide with a spinel-type crystalline structure similar to that of CuFe2O4. The low-temperature reduction of Cu2+ to Cu0 accelerates the Fe2O3 → Fe3O4 and FeO → Fe0 transformations. In the presence of oxygen we did not observe the reduction of Cu and Fe to the metallic state. This means that the oxidation of CO over FeAl and CuFeAl composite catalysts proceeds via a redox mechanism.