(Zr-0.8,Sn-0.2)TiO4 (ZST) thin films (similar to150 nm) were grown on Pt/Ti/SiO2/Si(100) and fused quartz glass substrates by radio frequency (rf) magnetron sputtering. The microstructure and the surface morphology of ZST thin film have been studied by Xray diffraction (XRD) and atomic force microscopy (AFM). The optical properties of ZST thin film were obtained by spectroscopic ellipsometry and UV-Vis spectrometry for the first time. The optical band gap was found to be 3.30 eV of indirect-transition type. The low frequency (1 kHz-1 MHz) dielectric properties of ZST thin film were also discussed. The temperature coefficient of capacitance (TCC) of ZST thin film is about 80.2 ppm/degreesC at I MHz. The dielectric constant and dielectric loss at 100 kHz are 36.6 and 0.0069, respectively. The large dielectric loss compared with that of ZST ceramic is caused by the structure disorder in the thin film. (C) 2003 Elsevier Science B.V. All rights reserved.