The flexible ITO films were fabricated on PET substrate by Ion Beam Assisted Deposition(IBAD), and the effects of SiO2 buffer layer on the properties of ITO films were researched. The properties of ITO films were studied using X-ray diffraction (XRD), UV-VIS spectrometer, four-point probe and optical profiler. The results show that the SiO2 interlayer between ITO films and PET results in an increase of X-ray peak intensity of ITO film and a decrease of resistivity to 1.21×10-3 Ω·cm; in addition, the transmittance decreases to 85% and the surface is relatively smooth. The resistivity of the ITO films bent to some extent keeps some stability