In this study, the electrical properties, optical properties, and microstructures of 1 wt% ZnO-doped (Zr0.8Sn0.2)TiO4 thin films prepared by the sol-gel method on various heat-treatment temperatures and heat-treatment times were examined. The surface structural and morphological characteristics analyzed by X-ray diffraction, scanning electron microscopy, and atomic force microscope were sensitive to the deposition conditions, such as heat-treatment time (15-60 min) and heat-treatment temperature (250-450 degrees C). All the films exhibited ZnO-doped (Zr0.8Sn0.2)TiO4 (111) and (101) orientations perpendicular to the substrate surface, and the grain size was increased with increasing heat-treatment temperature and time. The optical transmittance spectroscopy further revealed high transparency (over 80%) in the wavelength range of 400-800 nm of visible region. At a heat-treatment temperature level of 250 degrees C and a heat-treatment time of 15 min, the ZnO-doped Zr0.8Sn0.2TiO4 films were found to possess a dielectric constant of 21 (at 1 MHz), a dissipation factor of 0.23 (at 1 MHz), and a leakage current density of 1.87 x 10-8 A/cm2 at an electrical field of 50 V/cm.