Two　sodium　heat-pipe　fixed　point　furnaces　(SHPF-1,　SHPF-2)　developed　at　the　National　Institute　of　Metrology　(NIM)　are　described,　and　their　vertical　temperature　uniformities　are　measured.　When　the　temperatures　of　the　these　two　furnaces　are　controlled　about　2°C　and　3°C　respectively,　below　the　freezing　point　of　the　aluminum,　the　largest　temperature　differences　did　not　exceed　15mK　and　11mK　in　a　distance　about　150mm　along　the　reentrant　well　of　the　aluminum　point　cell,　respectively.　These　temperature　uniformities　are　compared　with　those　of　foreign　similar　sodium　heat　pipe　furnaces.　Additionally,　factors　influencing　isothermal　characteristics　of　fixed　point　furnaces　are　analyzed.