To　explore　the　application　of　the　gas-controlled　heat-pipe　in　metrology,　the　thermal　characteristics　of　the　gas-controlled　sodium　heat-pipe　furnace　is　researched.　The　best　temperature　control　position　of　the　furnace　is　found　without　pressure　control,　the　temperature　stability　and　uniformity　both　in　the　single　thermometer　well　and　among　different　thermometer　wells　are　studied,　and　two　different　winding　modes　of　heating　wires　are　discussed.　Experimental　results　show　that　the　temperature　stability　reaches　±0.836　4　mK　within　15　min,　controlling　heat-pipe　inner　temperature　at　655　°C,　and　the　gas　line　pressure　at　7.840　kPa.