The present invention provides a piezoelectric film acoustic resonator, which comprises a substrate, a first electrode disposed over the substrate, a piezoelectric film disposed over the substrate and covering at least a portion of the first electrode and a second electrode disposed on a surface of the piezoelectric film away from the first electrode, one end of the first electrode extends in the direction away from the piezoelectric film to form a first extended pad, one end of the second electrode extends in the direction away from the first extended pad to form a second extended pad, the first extended pad comprises a first protruding reflection grating on the surface away from the substrate, the second extended pad comprises a second protruding reflection grating on the surface away from the substrate. The configuration can reduce the impact on acoustic performance while improving the quality factor.