As　a　new　type　of　welding　heat　source,　hollow　cathode　centered　negative　pressure　arc　(HCCNPA)　has　evenly　distributed　energy　density　in　the　center　of　the　arc　and　a　higher　energy　gradient　at　the　boundary　in　comparison　with　traditional　gas　tungsten　arc　(GTA).　With　these　changes,　the　brightness　of　the　cathode　increased　significantly,　which　is　the　effect　of　inner　arc　plasma　on　the　hollow　cathode.　To　better　understand　of　this,　in　present　study　the　measurements　of　energy　distribution　between　anode　and　cathode　in　HCCNPA　were　performed　respectively　by　calorimetric　calculation.　Experiments　were　conducted　to　evaluate　the　influence　of　welding　parameters　on　heat　distribution　of　HCCNPA,　and　the　results　were　compared　with　conventional　GTAW　process.　It　was　found　that　the　application　of　negative　pressure　in　the　hollow　cathode　greatly　modified　the　energy　distribution　between　anode　and　cathode.　Though　the　energy　demand　of　maintaining　a　stable　arc　increased　with　the　application　of　negative　pressure　which　reflected　as　the　increase　of　arc　voltage,　the　total　energy　used　to　electrode　became　lower.　In　particular,　the　energy　in　cathode　increased　and　that　in　anode　decreased　as　the　negative　pressure　applied,　and　these　differences　increase　as　the　current　and　arc　length　increase.　Otherwise,　the　application　of　negative　pressure　in　the　hollow　made　the　result　arc　constrained,　so　the　HCCNPA　has　a　more　evenly　distributed　energy　density　in　the　center　and　a　higher　energy　gradient　at　the　boundary　in　comparison　with　the　conventional　GTA,　which　would　enable　the　development　of　high　quality　applications.　(C)　2016　The　Society　of　Manufacturing　Engineers.　Published　by　Elsevier　Ltd.　All　rights　reserved.