In this letter we report the fabrication and structural properties of ZnO thin films grown on GaAs，Au/GaAs，Si and glass substrates by rf magnetron sputtering. The x-ray diffraction data indicated that all the ZnO films were pure c-axis oriented and the rocking curves showed that the full-width at half maximum(FWHM) of ZnO(002) peak of ZnO/Au/GaAs films is as small as 2.41°. The SEM images showed better surface for the ZnO films grown with Au buffer. The surface acoustic wave properties of IDT/ZnO/GaAs filter were measured by HP8753C network analyzer. The results indicated that the insertion loss is only 10.4dB and the electric efficiency can be up to 84.1% using the 5.6μm-wavelength IDT.