Hard coating can be used as damping treatment. An interfacial damping model, based on the interface slip mechanism, is presented. Interfacial damping ( ) can be expressed as a quadratic function of the interface adhesion strength (N). It means that there exists a suitable bonding strength ( ) which makes the interfacial damping capacity obtain the maximum value. The model can be used to evaluate the damping performance and the interfacial adhesion condition of a hard coating structure.