Based　on　the　properties　and　stress　characteristics　of　space　frame　structure　under　fire,　according　to　the　high　temperature　properties　ruled　in　Eurocode　the　load-carrying　capacity　of　the　welded　hollow　spherical　joint　under　constant　high　temperature　are　tested　experimentally,　the　three　joints　are　step　loaded　under　three　different　temperatures-500°C,　600°C　and　700°C　until　they　are　failed.　The　temperature　field　and　the　load-displacement　curves　under　the　high　temperature　are　got.　The　failure　mode　of　welded　hollow　spherical　joint　under　high　temperature　are　also　decided.　The　results　could　be　the　theory　basis　for　the　joint　design　in　future.