Abstract: To explore the micro mechanism of damping properties of the metal coating.In this paper,Al,Ti and TiAl alloy coatings on stainless steel were prepared by magnetron sputtering.The phase,microstructure and elements of the coating were studied by X-ray diffraction,scanning electron microscope and energy dispersive spectroscopy.Resultsshow that the Al coating prepared by the single target magnetron sputtering has a typical lamellar crystal structure and the Ti coating has a columnar microcrystalline structure.The TiAl alloy coating prepared by double target co-sputtering is an alloy micro cluster structure with Al crystal as the core and microcrystalline Ti as the core.We then tested of damping properties of the metal coating and matrix structure.There are Q¹ peaks in the frequency range of 31-35 Hz for Al,Ti,TiAl alloy and stainless steel matrix.When the frequency is 57 Hz,there are obvious Q¹ peaks in Al,Ti and TiAl alloy coated samples.The peak value is about 0.016.There is no peaks at this value in stainless steel samples without coating.In the Q¹ curve of strain amplitude at 57 Hz,the damping property of micro cluster crystalline TiAl alloy coating is the strongest,that of columnar crystalline Ti coating is the second,and that of sheet crystalline Al coating is the weakest.We conclude that there is a direct correlation between the crystal structure and the damping property of metal coating.The main reason for damping is the relaxation of disordered crystal structure and the internal friction of nano gap at the grain boundary.