A　novel　welding　arc　named　hollow　cathode　centered　negative　pressure　arc　(HCCNPA)　is　proposed　in　this　paper.　This　is　an　arc　discharge　being　ignited/maintained　at　a　hollow　cathode　whose　cavity　is　negatively　pressurized.　The　authors　designed　an　experimental　system　to　stabilize　the　arc　and　monitored/studied　the　arc　behavior　using　a　high-speed　image　processing　system.　Arc　behaviors　were　studied　and　correlated　to　the　process　parameters.　It　was　confirmed　that　the　negative　pressure　constricted　the　arc　and　elevated　the　tungsten　temperature.　The　dynamic　change　in　the　arc　characteristics　were　reflected　in　the　arc　voltage　waveform.　In　addition,　the　arc　length,　current,　and　inner　pressure　all　affected　the　characteristics　of　the　resultant　arc.　To　examine　the　distribution　of　this　novel　arc　as　a　heat　source,　stagnation　ablation　experiments　were　designed　and　conducted　on　Grade　D　steel　workpieces.　Analyses　on　the　bead　appearance,　cross　section,　and　microstructure　provided　the　evidence　to　support　the　claim　that　the　resultant　arc　in　the　proposed　HCCNPA　process　has　a　more　evenly　distributed　energy　density　in　the　center　and　a　higher　energy　gradient　at　the　boundary　in　comparison　with　the　conventional　GTA,　as　have　been　expected.