Abstract: In order to define the impact of weld on brittle fracture of side-plate reinforced joint，this paper studied the fracture criterion distribution features along different paths and analyzed rupture index characteristics according to the two models either with or without weld at the flange junctioning residual stress． Based on the above research，the results show that weld at the flange junction of beam and column residual stress has a certain influence on producing brittle fracture at the root of the joint．