Using finite element simulation software, the film bulk acoustic resonator（FBAR） model was established. The study focused on investigating the effects of different electrode shapes (rectangular, trapezoidal, circular, and regular pentagonal) and apodization angles (30°, 36°, 40°, and 45°) on parasitic resonances under different resonant areas (3 600-10 000 μm2). The smith impedance curves and non-circularity values were obtained. The study also explored the suppression effects of stepped load structures on lateral acoustic wave leakage. The simulation results show that the non-regular pentagonal electrode shape with a apodization angle of 40° exhibits the best suppression effect on parasitic resonances. For the resonant area of 3 600 μm2, its non-circularity value is 6.45%, which is comparable to the rectangular electrode at a resonant area of 10 000 μm2. The designed stepped load structure significantly enhances the quality factor at the parallel resonance point. With a lateral dimension of 60 μm, the second-order electrode load structure achieves a quality factor of 1 378, which is 10.07% higher than that of the structure without electrode load.