A SiO2 buffer layer was introduced to deposite high c-axis oriented LiNbO3 film on Si substrate by radio-frequency(RF) magnetron sputtering technique.The crystal orientation,composition and surface morphology of the thin films were characterized by the X-ray diffraction(XRD),Fourier transform infrared spectrometer(FTIR),and scanning electron microscopy(SEM),respectively.The effects of the amorphous SiO2 buffer layer on the c-axis orientation of LiNbO3 film were investigated.The results show that when the thickness of amorphous SiO2 buffer layer is from 10 nm to 50 nm,the c-axis orientation of LiNbO3 film deposited on Si(100) substrate is enhanced with the increase of the thickness of the amorphous SiO2 buffer layer,but when the thickness of the buffer layer exceeds 30 nm,the change of the c-axis orientation is little;the LiNbO3 film deposited on Si(111) substrate has high c-axis orientation and good crystalline quality,when the thickness of amorphous SiO2 buffer layer is 10 nm.The texture coefficient of the c-axis orientation of LiNbO3 film is 90%,but the c-axis orientation of LiNbO3 film is weakened as the thickness of the buffer layer increases.