A bulk acoustic wave resonator with a mass adjustment structure comprises a supporting layer, a lower metal layer, a piezoelectric layer, an upper metal layer and a mass adjustment structure. The supporting layer is formed on a substrate. The supporting layer has a cavity, and the cavity has a top-inner surface. The lower metal layer is formed on the supporting layer. The piezoelectric layer is formed on the lower metal layer. The upper metal layer is formed on the piezoelectric layer. An acoustic wave resonance region is defined by an overlapping region of projections of the upper metal layer, the piezoelectric layer, the lower metal layer, the supporting layer and the cavity. The acoustic wave resonance region is divided into a peripheral region and a central region. The mass adjustment structure comprises a peripheral mass adjustment structure formed on the top-inner surface within the peripheral region.