Abstract: In this paper,finite element calculation and analysis was carried out on the welded hol-low spherical joint using general purpose structure analysis program SAP6.Investigation was specially made for stresses at the junction of the steel tube and the hollow sphere.The calculation was carried out on more than fifty different size joints.The result shows that the maximum stress is the radial stress occuring at the juction of steel tube and the hollow sphere.Serious stress concentration phenomenon exists in this region.The magnitude of the stress concentration factor varies with the sphere diameter,the tube diameter,the sphere thickriess and the tube thickness regularly.In order to analyze the stress and deformation of spherical joint completely and provide data to obtain more reasonable formulas,characteristic curves were plotted in this paper.