C-axis-oriented and fine structural ZnO films were successfully prepared on Langasite substrate(LGS, La3Ga5SiO14) by rf magnetron sputtering. The crystalline of the films was determined by grazing incident angle X-ray diffraction (XRD), the surface microstructure of films was investigated by Scanning electron microscop(SEM) and the atom composition ratio O/Zn of films was determined by Energy Dispersive X-ray Spectroscopy (EDS). Different RF powers (100W, 150W and 200W) were used to deposit the films. The results showed the films prepared in the research were all polycrystalline hexagonal ZnO films. The optimal ZnO films prepared at the RF powers(200W) had the highly c-axis-oriented microstructures, dense surface morphology, best composition ratio (0.99) and the film thickness was 1.44 μm. Surface acoustic wave (SAW) measurement was used to evaluate the acoustic properties of this new composite substrate (ZnO/LGS). ZnO films on LGS can effectively enhance the SAW electromechanical coupling coefficient value.
