Abstract: Under different process stages and different treatment parameters, the surface layer of hot-rolled steel formed an iron oxide scale layer, and its microstructure would affect the formulation of subsequent treatment process parameters. The phase distribution of the iron oxide scale layer on the surface of a hot-rolled steel plate was analyzed by comprehensive application of various functions of electron probe. The results show that six analysis methods were selected to analyze the state of oxide scale in the test, and each method could obtain ideal result. The analysis results could provide data support for optimizing the process parameters of hot rolled steel, improving product quality and studying the oxidation behavior of steel.