Abstract: In the pretreatment process of sintered NdFeB permanent magnetic materials, using the electrolytic ash removal process can obtain coatings with more excellent performance. Experimental results show that the parameter control of the electrolytic ash removal process is the key for NdFeB permanent magnetic materials to achieve good coatings. The selected electrolytic ash remover is of strong alkaline ratio, which effectively avoids the corrosion of the material substrate. Meanwhile, the effects of the concentration and temperature of the electrolytic ash remover, as well as the anodic current density on the coating adhesion, were studied. The optimal electrolytic ash removal process conditions were determined through orthogonal experiments. The ultrasonic ash removal process was compared synchronously, further confirming the superiority of the electrolytic ash removal process in terms of coating adhesion, corrosion resistance, and influence on material properties.