The coating technics by electroless deposition with Ni-P alloy on the surface of NdFeB magnets were optimized by orthogonal experiments. The microstructure and morphology of NdFeB magnets with electroless Ni-P deposit from an acidic bath and an alkaline bath were studied and compared. The corrosion rates of Ni-P deposites and substrate were measured in the NaCl solutions of 3.5wt%, the HCl solutions of 10vot% and the NaOH solutions of 20wt%. The corrosion characteristics of Ni-P deposits were evaluated for the two baths by electrochemical potentiodynamic polarization and impedance techniques. The results show that both deposits enhanced the corrosion resistance of substrate. The Ni-P deposit from the acidic bath provides a better protection due to the amorphous structure, and the continuous and compact cystiform microstructure on the surface of coatings.