Abstract: Effects of Nd substitution for sintered Pr-Nd-Fe-B magnets corrosion resistance were investigated, via mass loss of the magnets by HAST, and potentiodynamic polarization curves under different corrosive mediums. The result shows that the mass loss reduced, and the corrosion potential moved positively to different extent within the condition of 0.1 mol/L HCl, 3.0 % NaOH and 3.5 % NaCl aqueous solution, after the rare-earth element Pr of the sintered Pr-Nd-Fe-B magnet completely been substituted, which indicates the better resistance against electrochemical corrosion. The microstructure of the magnet using Nd by SEM in comparison with the(Pr-Nd) one suggests that the grain boundaries becomes more clear and continuous, and the Nd-rich phase at triple junctions is reduced. Through which the corrosion rate of the grain boundaries is slowed down, and as is effective to the corrosion resistance.