ZnO thin film, as a promising piezoelectric material, possesses unique electrical, acoustical, and optical properties. In this paper, AI/ZnO thin film was deposited on Si wafer by magnetron sputtering. Highly oriented, dense, and fine-grain polycrystalline ZnO films with excellent surface flatness and high resistivities have been obtained, when the sputtered gas pressure was 0.9 Pa, the temperature was 200 degrees C and the Ar-to-O-2 ratio was 1:3. A 780MHz surface acoustic wave filter (SAWF) has been successfully fabricated using the Al/ZnO film on silicon wafer.