Abstract: The carbon fiber/bismaleimide (T300/QY8911) embedded co-cured composite damping structure (ECCDS) specimens were manufactured by pressed-film process and brush coating process. The moisture absorption properties of T300/QY8911 composite damping structure specimens were studied, and the relationship between moisture absorption rate and the thickness of damping layer was obtained. The interlayer bonding properties of moisture absorption treated composites made by the two processes above were investigated, and the relationship between the thickness of damping layer and the maximum interlamination shear stress was analyzed. Results show that the ECCDS with perforated viscous-elastic damping layer can increase the interlaminar bonding properties after moisture absorption treatment, and provide a foundation for the theoretical design and application research of ECCDS.