With　the　rapid　development　of　application　fields,　such　as　the　green　energy　industry,　has　resulted　in　increased　demand　for　magnetic　characteristics,　especially　the　coercivity　(Hcj).　In　this　paper,　two　types　of　(Nd,　Dy)　-Fe　-B　magnets　with　comparable　Hcj　values　were　prepared　using　by　grain　boundary　diffusion　(GBD)　method　and　dual　alloy　(DA)　method.　The　composition,　microstructure,　domain　structure,　and　magnetization　reversal　process　of　GBD　and　DA　magnets　were　subjected　to　comparison.　Additionally,　an　analysis　of　the　specific　coercivity　mechanism　was　also　conducted　by　fitting　the　Brown＇s　equation.　The　results　of　composition　and　microstructure　analysis　revealed　the　formation　of　core-shell　structural　grains　were　formed　in　both　GBD　and　DA　methods.　Specifically,　the　GBD　method　exhibited　a　higher　concentration　of　Dy　in　the　shell,　constituting　26.8　%　of　the　total　rare　earth　(RE)　content.　In　contrast　the　DA　magnets　had　Dy　accounting　for　15.8　%　of　the　total　RE　content　in　the　shell.　This　discrepancy　was　identified　as　the　primary　factor　contributing　to　the　superior　efficiency　in　enhancing　the　coercivity　(Hcj)　observed　in　the　GBD　method.　The　fitting　results　showed　that　GBD　magnets　were　more　inclined　to　nucleate　in　the　core　region　in　grain,　whereas　DA　magnets　nucleate　at　the　edge　of　the　grain　shell　layer.　Both　the　observation　of　magnetic　domains　and　magnetization　reversal　processes　analysis　revealed　that　the　demagnetization　process　in　GBD　magnets　is　more　uniform,　which　leads　to　better　squareness.　Our　finding　can　provide　theoretical　and　experimental　basis　for　the　preparation　of　high　-performance　Nd-Fe-B　magnets.