Through X-ray photoelectron spectroscopy, by the aid of Ar+ sputtering, chemical composition and the valence state of elements on surface and at depth of TiO2-SiO2 thin films and metal substrates have been studied. Results show that: on surface, elements of Cr, Mn, Ti, Fe exist in the form of their respective stable state, but Si is unstable and exhibits stoichiometrical disturbance when heat treated at 800 degrees C; at depth, after sputtering for 5 minutes and 17 minutes, elements of Cr, Mn, Ti and Ni exist in the form of their respective stable state, but Si and Fe are unstable and exhibit stoichiometrical disturbances; at depth, after sputtering for 57 minutes, all of the Cr, Mn, Ti, Si, Ni and Fe exist in the form of their respective stable state. Results of chemical composition and their content by weight percent of TiO2-SiO2 thin films and metal substrates reveal that: Fe, Cr, and Mn diffuse from metal substrates to the thin films in scale; Ni diffuses few and Si collects to the metal substrate surface.