The Cu electroplating on sintered NdFeB was conducted with hydroxyethylidene diphosphonic acid (HEDP) as a cyanide-free alkaline plating electrolyte and potassium pyrophosphate as an auxiliary complexing agent. Meanwhile, the plating process was optimized through cyclic voltammetry (CV), cathodic current efficiency, Hall tank experiments, scanning electron microscopy (SEM) and other means; then the plated coatings were characterized by means of SEM and scratch test etc., and their corrosion resistance was assessed by salt spray test. The results showed that the coatings with smooth surface, defect free and good adhesion to the NdFeB substrate may be acquired with an electrolyte composed of CuSO₄·5H₂O 22.5 g·L^-1, HEDP 60 g·L^-1, K₄P₂O₇ 40 g·L^-1 and K₂SO₄ 10 g·L^-1 of pH = 10, at 50 ℃, by stirring rate of 200 r·min^-1, and current density of 0.6 A·dm^-2. The corrosion resistance of the Cu-plating is close to that of conventional Ni-Cu-Ni plating; Besides, the surface magnetic and magnetic flux results show that the magnetic shielding effect of direct Cu plating on NdFeB surface is smaller than that of Ni-Cu-Ni plating.