Rotating　diffusion　technology　is　especially　suitable　for　mass　production　of　small-sized　magnets.　In　this　paper,　a　large　mass　rotating　diffusion　with　2500　pieces　of　small-sized　magnets　was　conducted　to　enhance　coercivity.　At　the　same　time,　the　uniformity　of　the　properties　was　studied.　Taking　both　magnetic　properties　and　yield　rate　into　account,　we　obtained　the　optimal　parameters　of　the　rotating　diffusion　at　710　degrees　C　for　5　h,　following　a　two-stage　annealing　process　at　940　degrees　C　for　5　h　and　at　500　degrees　C　for　3　h.　Thus,　the　coercivity　of　the　magnet　could　increase　from　14.05　kOe　to　23.06　kOe.　EPMA　results　show　that　most　Tb　enriches　the　surface　of　the　magnets,　and　some　Tb　is　diffused　into　the　grain　boundary　phase　forming　magnetic　isolation　during　the　rotating　diffusion　process.　After　the　two-stage　annealing　process,　many　(Nd,Tb)(2)　Fe14B　substitutional　phases　with　higher　anisotropy　field　are　formed　around　the　epitaxial　layer　of　the　main　phase　increasing　the　coercivity　of　the　magnet.　Discrete　analysis　and　a　linear　fit　show　excellent　uniformity　of　the　properties　in　this　massive　rotating　diffusion　process.