In this paper, the high-overtone bulk acoustic resonators (HBAR) were fabricated based on the scandium-doped AlN thin films, and the effect of scandium(Sc) doping concentration on the material properties of AlN piezoelectric thin films as well as the performance of devices were investigated, The results showed that, as the Sc mole fraction increased from 0 to 25%, the piezoelectric stress coefficient e33 increased and the stiffness constant CD33 decreased, resulting in an increase of the electromechanical coupling coefficient k2t of Al1-xScxN piezoelectric film from 5, 6% to 15, 8%, thereby increasing the effective electromechanical coupling coefficient (k2eff) of HBAR device by a factor of three, At the same time, when the Sc mole fraction was up to 25%, the sound velocity of the Al1-xScxN film piezoelectric film was reduced by 13%, and the acoustic loss was increased, resulting in a decrease of the resonant frequency and quality factor Q of the HBAR device,