Due　to　an　excellent　temperature　flattening　ability,　annular　sodium　heat　pipes　operating　from　500　A　degrees　C　to　1200　A　degrees　C　have　been　widely　used　as　liners　for　isothermal　furnaces　to　provide　uniform　and　stable　temperature　zones.　In　order　to　develop　the　capabilities　to　fabricate　liquid-metal　heat　pipes,　an　apparatus　for　fabricating　sodium　heat　pipes　was　set　up　at　the　National　Institute　of　Metrology　(NIM),　China.　In　this　paper,　the　newly　developed　fabrication　apparatus,　the　detailed　procedures　for　manufacturing　sodium　heat　pipes,　the　sodium　heat　pipes,　the　constructed　furnaces　for　realizing　the　aluminum　freezing　point,　and　their　isothermal　characteristics　are　described.　The　experimental　results　showed　that　the　biggest　temperature　differences　within　150　mm　from　the　bottom　of　the　thermometer　well　in　an　aluminum　point　cell　placed　in　the　sodium　heat-pipe　furnaces　were　better　than　15　mK,　when　the　temperatures　of　the　furnaces　were　controlled　at　approximately　657　A　degrees　C.