Abstract: Taking FeCrAl alloy coating as an example, combined with X-ray photoelectron spectroscopy (XPS) and focused ion beam (FIB) technology, the oxidation behavior of FeCrAl coating in 1 200 ℃ water vapor environment has been studied. XPS and FIB methods enable the detection and observation of interface layers, chemical states, real structures, and etc. of materials with depth. It has the advantages of intuitive and informative (content, chemical state and morphology). It provides the theoretical and practical basis for the application of the method in a wider material system.