Using a highly conductive ZnO(ZnAl2O4) ceramic target, c-axis-oriented transparent conductive ZnO:Al2O3 (ZAO) thin films were prepared on glass sheet substrates by direct current planar magnetron sputtering. The structural, electrical and optical properties of the films (deposited at different temperatures and annealed at 4001C in vacuum) were characterized with several techniques. The experimental results show that the electrical resistivity of films deposited at 3201C is 2.67-10-4Ocm and can be further reduced to as low as 1.5-10-4Ocm by annealing at 4001C for 2h in a vacuum pressure of 10-5 Torr. ZAO thin films deposited at room temperature have flaky crystallites with an average grain size of B100nm; however those deposited at 3201C have tetrahedron grains with an average grain size of B150nm. By increasing the deposition temperature or the post-deposition vacuum annealing, the carrier concentration of ZAO thin films increases, and the absorption edge in the transmission spectra shifts toward the shorter wavelength side (blue shift).