SnO₂-Al₂O₃ (SAO) binary thin films were prepared on slide glasses substrates by RF magnetron sputtering. The influence of the substrate temperature on the micrographs, crystal structures, electrical and optical properties were analyzed by using the scanning electron microscopy (SEM) images, X-ray diffraction (XRD) patterns, four-probe measuring, UV-IR and photoluminescence (PL) spectra. By increasing substrate temperature, the grain sizes of SAO binary films were enhanced, uniform patterns and large size grains indicate a better surface morphology and crystallinity of SAO films, which were verified by SEM and XRD investigations. All the films have a high average transmittivity of ~80%-90% in visible light region 400-800nm. The calculated band gap was in a range of ~4.11-4.14eV, and the measured sheet resistances of SAO films were in a range of ~7.0 to ~9.4 . By proper choosing sputtering temperature, the band gap can be widened, and the sheet resistances can be reduced. The PL emissions from the films in UV and red bands were also observed. These polycrystalline SAO films can be used in the application of transparent conductive oxide (TCO) films, solar cell windows, sensors, as well as lighter emitters.