Abstract: In order to accurately simulate the propagation of seismic waves in the coupled acoustic-elastic media, this paper applies the nodal discontinuous Galerkin method to seismic wavefields simulation in 3D coupled acoustic-elastic media. We provide a detailed derivation of the numerical formulations, including the upwind numerical flux at acoustic-acoustic, acoustic-elastic and elastic-elastic interfaces. Subsequently, numerical experiments are conducted for different coupled models, which includes the coupled models with flat interface, curved interface and irregular topography. By comparing the numerical solutions with those from spectral element method, the accuracy and the ability of handling coupled boundaries of the proposed scheme are verified. Finally, the method is applied to a 3D overthrust model to validate its capability in dealing with complex geological structures.