Abstract. This This Al 2 O 3 , SiO 2 , Ta 2 O 5 , Nb 2 O 5 , TiO 2 single layer oxide thin film are prepared by using ion beam sputtering deposition technology. The oxide films infrared optical constants are fitted by infrared variable elliptic polarization Angle spectrum instrument (IR -VASE), the results show that the fitting optical constants n, k in line with the material properties. The oxide thin film surface roughness are analyzed by AFM (Nanosurf Easysc -2), and research findings show the compact structure of oxide film and RMS of surface roughness in 0.1 nm, which scattering is smaller.