A 200nm Ti film was deposited on a polished mullite ceramic substrate at 200℃ by electron beam evaporation,and annealed under high vacuum conditions.Secondary ion mass spectrometry (SIMS),Auger electron spectroscopy (AES) and X-ray diffraction measurement (XRD) were employed to probe the solid interfacial reaction between Ti and mullite from 200—650℃ for the first time.The results show that the first deposited Ti atoms have formed Ti—O bond with O on mullite surface during the deposition,and trace elemental Al and Si atoms have been segregated,but interfacial range is very narrow.It was broadened a little after the sample annealed at 450℃ for an hour.Interfacial reaction happened violently when the annealing temperature was 650℃ for an hour,and the sample mainly consisted of four laminated structures which in turn were TiO+Ti,Ti3Al,Ti3Al+TiSi2 and mullite ceramic substrate.