Grain boundary diffusion technology can reduce the amount of heavy rare earth and effectively save heavy rare earth resources; Reduce the production cost of magnets and improve the comprehensive cost-effectiveness of products. For magnets with the same performance, grain boundary diffusion technology uses less heavy rare earth elements than traditional technology. Compared with traditional technology, grain boundary diffusion technology can prepare magnets with higher comprehensive performance, such as 54SH, 54UH, 50EH, 45AH, 42TH; Some of the magnets have Hcj (kOe)+(BH) max (MGOe)>82.