<p>This study develops a trans-scale dynamic shear-lag model based on strain gradient theory and the Gurtin-Murdoch model to investigate the dynamic behaviors and wave attenuation performance in nacre-like staggered composites. This model provides an analytical expression for the wave attenuation factor of staggered composites that incorporate nanoscale tablets and matrices. Our model shows that the strain gradient and surface energy effects of the nanoscale matrix and tablets significantly influence the dynamic behavior and wave attenuation performance of staggered composites. The strain gradient intensifies the localization of stress wave amplitude in tablets and matrices, while interface energy mitigates this effect. As the strain gradient increases or the interface modulus decreases, the first bandgap shifts to higher frequencies, resulting in a diminished low-frequency filtering capability. Furthermore, we show that the width and position of the first bandgap exhibit a non-monotonic variation with microstructural parameters, such as Young’s modulus of the tablets and the thickness of the matrix. The results of this study provide valuable insights for designing advanced composites with nanoscale structures to achieve superior dynamic performance.</p>