Arc　characteristics　are　found　greatly　changed　by　the　negative　pressure　from　the　hollow　cathode.　These　changes　affect　the　distribution　of　arc　pressure,　arc　plasma　flow　and　temperature　along　the　arc　column.　The　characteristics　of　HCCNPA　(hollow　cathode　centered　negative　pressure　arc)　along　the　arc　column　were　investigated　in　this　study　to　understand　the　changes　and　influences.　It　was　found　that　the　negative　pressure　applied　to　the　cathode　reduced　the　arc　pressure　and　the　arc　radius,　and　complicated　the　plasma　flow　distribution　with　a　clear　zero-speed　dividing　line　in　the　arc　column.　Above　the　boundary　line,　the　plasma　in　the　middle　of　the　arc　column　flowed　to　the　cathode,　and　the　peripheral　plasma　flowed　to　the　anode,　presenting　two　peak　values　in　the　arc　pressure　distribution.　The　inner　negative　pressure　also　could　adjust　the　total　arc　force　acting　on　the　work-piece.　Under　the　same　inner　negative　pressure　conditions,　the　difference　in　arc　force　between　GTA　(gas　tungsten　arc)　and　HCCNPA　did　not　change　at　varying　arc　lengths.