Approach　a　trade-off　between　properties　and　cost　for　sintered　Nd-Fe-B　magnets　in　grain　boundary　diffusion　(GBD)　helps　widen　their　application.　In　this　study,　we　fabricated　GBD　Nd-Fe-B　magnets　via　solid-liquid　phase　separation　diffusion　(SepD)　with　DyH3　nanopowder　as　the　diffusion　source.　Investigations　and　comparisons　with　the　traditional　solid-liquid　phase　simultaneous　diffusion　(SimD)　magnets　were　made　regarding　the　liquid　phase　diffusion　(LPD)　temperature,　magnetic　characteristics,　microstructures,　diffusion　coefficient,　and　domain　morphology　of　SepD　magnets.　In　addition,　the　cost　was　calculated　and　compared　with　TbH3　SepD　magnets.　It　is　determined　that　the　optimal　LPD　temperature　of　DyH3　was　625　degrees　C.　Compared　to　the　SimD　magnet,　Dy　had　a　faster　LPD　rate　in　the　SepD　magnet,　which　leads　to　a　deeper　diffusion　depth　of　1200　&　mu;m.　Consequently,　the　SepD　magnet　develops　more　core-shell　structures.　Additionally,　SepD　could　prevent　the　development　of　anti-core-shell　formations　in　the　magnet＇s　surface　region.　As　a　result,　the　SepD　magnet　had　higher　comprehensive　magnetic　properties　and　coercivity　temperature　stability.　Impressively,　compared　to　TbH3　SepD　magnets,　the　cost　of　per　kOe　coercivity　enhancement　for　per　kilogram　magnets　of　DyH3　SepD　magnets　can　be　reduced　by　more　than　50　%.