Abstract: Based on the properties and stress characteristcs of space frame structure under fire,according to the high temperature propevties 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 ℃,600 ℃ and 700 ℃ 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.