A　trade-off　between　the　coercivity　and　other　magnetic　properties　(remanence　and　maximum　energy　product)　is　a　dilemma　in　current　grain　boundary　diffusion　(GBD)　Nd-Fe-B　sintered　magnets.　Here　we　report　a　new　solid-liquid　phase　separation　diffusion　method　for　Nd-Fe-B　magnets,　which　substantially　and　comprehensively　enhances　permanent　magnetic　performance,　especially　demagnetization　curve　squareness.　The　results　show　Tb　diffused　preferentially　into　the　inside　of　magnets　through　the　molten　Nd-rich　grain　boundary　phase　during　the　liquid　phase　diffusion　process.　Then,　uniform　core-shell　structures　were　formed　during　the　subsequent　solid　phase　diffusion　process.　This　new　GBD　strategy　increases　the　diffusion　depth　and　avoids　the　evident　Tb　gradient　that　cause　the　deterioration　of　the　magnetic　performance　of　current　GBD　magnets.　The　microstructure　and　magnetic　domain　evolution　in　the　Nd-Fe-B　magnets　diffused　with　both　current　and　newly-developed　techniques　were　also　compared　and　investigated.