Abstract: The effects of different oxygen content film structures on the microstructure and photoelectric properties of barium titanate films were studied and high-quality barium titanate films were prepared by radio frequency magnetron sputtering. Set the substrate heating temperature to 350 ℃, set the working pressure to 1.6 Pa, set the sputtering power to 150 W, and under the condition that the total sputtering time is 200 min. The barium titanate films with the sandwich structure of "poor oxygen + rich oxygen + poor oxygen" were constructed on the ITO substrate. The microstructure, morphology and element content of the film were characterized by XRD, SEM, XPS, and the dielectric constant and dielectric loss value of the film were obtained by LCR test and calculation. The experimental results show that the thickness of the prepared sandwich structure film is 810 nm, the average visible light transmittance can reach 55%, the dielectric constant of the film is 3.8, and the dielectric loss value is less than 0.18. Adopting "poor oxygen + rich oxygen + poor oxygen" sandwich structure is beneficial to improve the crystallinity of the barium titanate film, and is beneficial to increase the grain size of the barium titanate film, increase the dielectric constant of the barium titanate film, and reduce the dielectric constant of the barium titanate film.