The amorphous Te-In-Sb thin films were prepared by radio frequency sputtering. We investigated the reflectance and the transmittance of different compositions of Te-In-Sb films. The structure and its change were observed by TEM and electron diffraction. The effect of the Te-In-Sb composition on their optical properties, such as dielectric constant, absorbation coefficient and optical gap etc. are discussed. As a result, we find that TeselnaiSbsr .film may be a suitable medium for erasable optical disk.