Abstract: SiO2-TiO2 composite coating was prepared on the surface of carbon fiber by sol-dipping method. The influence of titanium-silica ratio，dipping methods，and dipping times on the coating was investigated.The phase composition and morpho- logy of the prepared samples were characterized by X-ray diffraction（XRD），scanning electronic microscopy（SEM），and transmission electron microscopy（TEM）.The oxidation resistant properties of the carbon fibers with composite coating were studied by static isothermal oxidation experiment.Results showed under the optimum dipping conditions，such as dipping 3 times in vacuum and ultrasonic environment and volume ratio of titanium to sol of 15∶1，the uniform and compact composite coating could be obtained.The composite coating banded well with the surface of carbon fiber and had a good oxidation resistance performance.Furthermore，the prepared layer was composed of anatase TiO2 and amorphous SiO2.The sample was continuously oxidized at 400 ℃ for 15 h and its mass loss rate was only 5.91%.

Key words: SiO2-TiO2 composite coating, carbon fiber, oxidation resistance, surface treatment