Abstract: In order to expand the application of nickel plating process in rare earth permanent magnet Nd-Fe-B devices，the influence of bottom nickel plating layer on the magnetic properties of products was studied in view of the attenuation of magnetic properties of Nd-Fe-B magnets caused by nickel plating pro⁃ cess. By adjusting the process of nickel plating on the bottom of Nd-Fe-B magnetic devices，the thickness of nickel plating on different bottom layers is obtained. The magnetic flux attenuation of magnetic devices is used as a measure to judge the influence of nickel coating thickness on magnetic properties. The test results show that when the bottom nickel layer is too thin，there is excessive corrosion on the product matrix，re⁃ sulting in serious magnetic flux attenuation. As the thickness of the bottom nickel layer increases to a cer⁃ tain appropriate range，the magnetic flux attenuation has the minimum value ; after the thickness of the bot⁃ tom nickel layer continues to increase，the magnetic output is shielded due to the ferromagnetic property of nickel，which further leads to the magnetic flux attenuation. The influence of bottom nickel plating thick⁃ ness on flux attenuation shows a trend of nonlinear gradient increase.

Key words: Nd-Fe-B, nickel plating, the bottom nickel, plating thicknes, magnetic flux, magnetic flux attenuation