The present disclosure provides a film bulk acoustic resonator and its fabrication method. The fabrication method includes providing a first substrate, and sequentially forming a first electrode layer, a piezoelectric material layer, and a second electrode layer, on the first substrate; forming a support layer on the second electrode layer and forming a cavity with a top opening in the support layer, where the cavity passes through the support layer; providing a second substrate and bonding the second substrate with the support layer; removing the first substrate; and patterning the first electrode layer, the piezoelectric material layer, and the second electrode layer to form a first electrode, a piezoelectric layer, and a second electrode.