Grain boundary diffusion technology can reduce the amount of heavy rare earths and effectively save heavy rare earth resources. Reduce the production cost of magnets and improve the comprehensive cost performance of products. For magnets with the same performance, the grain boundary diffusion process technology uses less heavy rare earth than the traditional process technology, and compared with the traditional process, the grain boundary diffusion process can prepare magnets with higher comprehensive performance, such as 56SH, 54UH, 50EH, 45AH, 42TH; Some of the magnets have Hcj(kOe)+(BH)max(MGOe)>83.