Abstract: Piezoelectric zinc oxide（ZnO） thin film was deposited by DC reactive magnetron sputtering and high overtone bulk acoustic resonator was fabricated on double-side polished fused quartz substrate.X-ray diffraction measurement shows that ZnO film is highly C-axis-oriented with a full width at half maximum（FWHM） 0.1624° which means good crystal quality.Scanning electron microscopy（SEM） shows the strong columnar structure oriented perpendicular to the smooth surface.The electrical characteristics of high overtone bulk acoustic resonator show multi-mode resonances,which mean that predominant longitudinal wave is excited by ZnO film.So the ZnO film could be used for applications of bulk acoustic wave devices and surface acoustic wave devices.With an indirect method,dielectric constant and dielectric loss factor of ZnO film at 870MHz were calculated to be about 5.24 and 1.07 respectively.With the dielectric loss factor further reduced,Q value of the BAW device would be much higher.