Machined　sintered　NdFeB　(S-NdFeB)　wastes　typically　contain　about　30　wt%　rare　earth　(RE)　elements　which　are　beneficial　as　supplemental　RE　resources.　In　this　work,　we　studied　one　type　of　oily　and　adhesive-containing　scraps,　and　developed　a　high-value　recycling　technique　based　on　surface　treatments-RE　manipulation-grain　boundary　diffusion,　specifically　to　directly　generate　multi-grade,　high-performance　S-NdFeB　magnets.　We　obtained　clean-surface　scraps　with　RE　mass　loss　of　less　than　4%　and　oxygen　content　below　2000　ppm　using　a　custom-made　solvent.　By　increasing　content　of　the　RE-rich　alloy　(Nd4Fe14B),　we　quickly　improved　the　performance　of　the　regenerated　magnets.　When　the　addition　was　15　wt%,　the　magnetic　properties　exceeded　that　of　the　original　magnet,　with　a　remanence　of　12.5　kG,　coercivity　of　17.79　kOe,　and　maximum　energy　product　of　37.95　MGOe.　Furthermore,　the　magnets　were　subjected　to　1　wt%　TbHx-diffusion　treatment,　which　further　optimized　the　performance,　and　the　coercivity　exhibited　a　50%　improvement　to　26.71　kOe,　which　greatly　expanded　the　application　in　motors　and　generators.　Microstructure　analysis　indicated　that　the　improved　magnetic　performance　of　the　regenerated　magnets　was　mainly　derived　from　the　restoration　of　the　RE-rich　phase,　and　the　Nd2Fe14B-(Nd/Tb)2Fe14B　core-shell　structure,　which　had　a　high　anisotropic　field.　Based　on　the　above　recycling　methods,　we　successfully　established　an　energy　conservation　and　efficient　recycling　line　for　S-NdFeB　wastes　at　a　scale　of　five　hundred　tons/year.　©　2023