Method for rust prevention of surface of neodymium iron boron magnet

The invention relates to a method for rust prevention of a surface of a neodymium iron boron magnet. The method comprises the following steps: soaking a neodymium iron boron magnet, which is subjected to mechanical processing and angle lapping, such as slicing, into water-based protecting liquid for 5-15 days, and washing to generate a layer of compact protecting film. The invention aims at rust prevention treatment of a buffer process with longer time for surface treatment of the next process after the neodymium iron boron magnet is mechanically processed and formed, and is a transition for sequential surface treatment for phosphorization, electroplating or organic coating. The method of soaking through solution has the advantages of simple process, short time, easiness in cleaning, and no influence on physical and chemical performances of the neodymium iron boron.