Purpose <p>In this paper, an ultra-lightweight chiral swastika ring phononic crystal (CSR-PnC) with impact resistance is proposed to suppress the anchor loss of piezoelectric MEMS resonators, thereby enhancing the impact resistance and reliability of the device while achieving miniaturization.</p> Methods <p>The structural unit consists of a swastika-shaped ligament connecting the central ring, which is different from the traditional phononic crystal designs. The band structure and frequency response of the structure were calculated using the finite element method, and the effects of key geometric parameters on the bandgap characteristics were systematically analyzed. In addition, the impact resistance of the structure was also analyzed.</p> Results <p>The structure has a bandgap in the wide frequency range of 115.22-171.76MHz, and compared with existing spider-shaped phononic crystals, its mass is reduced by 54%. Further studies on the effects of key parameters on the band gap revealed that the width w of the ligament has a significant impact on the lightweight design of the structure, while the outer diameter r1 of the central ring mainly adjusts the width of the band gap. In addition, impact analysis of the CSR-PnC structure indicates that the structure undergoes inward contraction and deformation when subjected to in-plane impact, demonstrating excellent impact resistance.</p> Conclusion <p>When applied to piezoelectric MEMS resonators, the anchor quality factor is increased by 108 times, and the insertion loss is reduced by 43.1%.</p>