Abstract: To address the challenges of large volume and narrow absorption bandwidth of micro-perforated panel-sound-absorption structures, this study proposes a parallel-coupled composite structure comprising a micro-perforated panel, sound-absorbing sponge, and cavity based on a parallel coupling mechanism. Using the transfer matrix method, a theoretical model for the absorption coefficient of the structure is established. The structural absorption characteristics are subjected to simulation analysis and experimental validation, followed by an exploration of the impact of structural design parameters on the absorption properties. The results demonstrate that the calculated outcomes of the theoretical model closely align with the results from acoustic simulations and impedance tube experiments, confirming the reliability of the established theoretical model. Analysis of different structural absorption characteristics reveals that the composite structure exhibits a broader absorption frequency band and higher absorption coefficient. By reducing the aperture and thickness of the micro-perforated panel, increasing the perforation rate, and thickening the sound-absorbing sponge, the overall sound absorption performance of the composite structure can be significantly improved. The findings of this study provide crucial insights for the development and optimization of acoustic structures in the field of transportation tools.