Abstract: Objectives Composite heterogeneous structures have been widely used in marine structures, and propagation characteristics of acoustic emission (AE) signals in composite structures and composite heterogeneous structures are investigated for the need of structural health monitoring. Methods Firstly, the calculation procedure of dispersion curves is developed based on a semi-analytical finite element method to calculate the group velocity dispersion curves of AE waves in composite panels. Then, ABAQUS is used to establish the finite element model and to investigate the dispersion characteristics and attenuation characteristics of AE signals in the composite structure. Finally, the time-frequency characteristics and mode conversion of AE signals in the T-shaped composite