Abstract: In this paper, the relationship between the performance of the mechanical impedance plate sound absorption structure and the plate area is studied. By analysis, the relationships between the acoustic quality factor and the relative acoustic resistance of the mechanical impedance plate absorption structure with plate area are obtained. Under the guidance of the relationships, the influence of increasing the plate area on the structural sound absorption performance is discussed. The results show that for the mechanical impedance plate sound absorption structure made of the same material, with the plate side length increasing from 0.1 m to 0.6 m, the frequency band of structural sound absorption moves toward low frequency and the bandwidth is slightly narrowed down; moreover, the peak value of the sound absorption coefficient increases first and then decreases. After the plate area being increased, the plate mass and the damping of the viscoelastic material need to be adjusted for keeping the structural sound absorption peak frequency constant, and meantime, the peak of the sound absorption coefficient can be increased and the sound absorption band can be widened. The study in this paper has guiding significance for practical engineering applications.