OM, SEM, TEM and XRD were used to analyze microstructure and oxidation layer of 430 stainless steel during hot rolling, and microstructure characteristic and oxidation layer evolution rule under high temperature deformation were studied. It is shown that microstructure after each pass under laboratory rolling condition is composed of austenite and ferrite, but there are significant differences in the size, morphology and distribution of dual phase microstructure. Oxidation layer of each pass consists mostly of Fe2O3, Fe3O4 and FeCr2O4. Thickness of surface oxide film decreases from 12μm to about 4~5μm as rolling pass increases. Compared to experimental result of laboratory rolling, because high-pressure descaling is used in practical production, meanwhile deformation amount is higher and surface quality of roller is better, oxidation layer of finished product is uniform, distributes continuously and has strong internal bonding force with matrix.