Electric　heaters　are　essential　for　converting　electrical　energy　into　thermal　energy.　High-voltage　electric　heaters　enable　efficient　voltage　distribution　across　hundreds　of　heating　units,　allowing　for　higher　power　output　while　maintaining　low　current　levels.　To　achieve　high-voltage　electric　heating,　the　thermal　conduct　ability　and　insulation　properties　of　the　filling　powder　are　crucial.　This　study　selects　aluminum　nitride,　boron　nitride,　silicon　nitride,　and　electrical-grade-　magnesium　oxide　as　filling　powders　to　manufacture　electric　heating　tubes,　the　breakdown　voltage　and　thermal　conductivity　were　tested.　The　aluminum　nitride　−tube　shows　the　best　breakdown　voltage　at　2.9　kV,　and　the　magnesium　oxide　−tube　shows　the　best　thermal　conductivity　at　1.4　W/(m·k).　Numerical　simulation　works　are　conducted　to　verify　the　accuracy　of　the　thermal　conductivity　calculation　results　and　simulate　the　heater＇s　temperature　field.　The　results　show　that　the　temperature　of　the　surface　and　resistance　wire　decrease　as　the　heat　transfer　coefficient　increases,　and　the　heat　transfer　coefficient　between　the　molten　salt　and　the　electric　heating　tube　cannot　be　less　than　3000　W/m2·K　when　the　power　density　of　the　resistance　wire　is　24.27　W/cm2　to　keep　the　surface　temperature　below　570.43℃.　Overall,　this　article　verifies　the　feasibility　of　aluminum　nitride　as　a　filling　material　for　high-voltage　electric　heating　tubes　through　experiments　and　simulations,　and　investigates　the　effects　of　power　and　heat　transfer　coefficient　on　the　temperature　distribution　within　the　heating　tubes　with　numerical　simulations.　©　2024