The film bulk acoustic resonator (FBAR) has the advantages such as small volume, high operating frequency and strong performance, so that it has wide application prospects in the field of filter. The most important functional layer of FBAR filter is the piezoelectric layer composed of piezoelectric materials. In this paper, AlScN piezoelectric films were prepared on 6 inch silicon substrates by magnetron sputtering. The AlScN films were analyzed and characterized. The results show that the preferred orientations for the (002) crystal face of AlScN films are excellent, the full width at half maximum (FWHM) of the rocking curve is 1.75°. The thickness uniformity of AlScN films is less than 0.6%. The film stress is 10.63 MPa, and the stress can be adjusted. FBAR resonators based on AlScN piezoelectric films were prepared. The electromechanical coupling coefficients were 7.53%. The results show that doping Sc in AlN can improve the effective electromechanical coupling coefficient, which is significance for studying the wide band FBAR filter.