Abstract: Sound transmission through metallic sandwich panels with corrugated core is investigated using the spaceharmonic method.A unit cell model is developed to provide the effective translational stiffness and rotational stiffness of the core,based on the periodicity of the microstructure of the panels.The developed model is first applied to analyze sound insulation of double-panel structure with air cavity.Obtained predictions are found to agree well with available experimental results.The model is then employed to investigate the effects of sound incidence angle and the inclination angle between face sheet and core sheet on Sound Transmission Loss (STL).Obtained results show that the inclination angle has a significant effect on STL and it is facility to avoid STL dips by altering the inclination angle.Moreover, it is found that sandwich panels with corrugated core are more suitable for the insulation of sound waves with small incidence angle.