The cold-formed square steel tubular with light weight has better seismic behavior and is suitable for construction in the area with high seismic fortification intensity. The reliability of joint connection greatly influence the safety reliability of structure, which’s restoring force characteristics under low cyclic loading need to be further researched. The finite element software ANSYS is used to do the research between two welded joints. The results show that : (1)Compared with typical welded joint, the ultimate bearing capacity of improved joint increase much, hysteretic curve is more plump, energy dissipation capacity enhance and stiffness degradation is slow. (2) Axial compression ratio has great influence on hysteretic behavior, bearing capacity and stiffness of common welded joints; however, there is a little effect on improved joint’s bearing capacity and stiffness. (3) After improved, the yield of joint has a longer yield platform, and under the same axial compression ratio condition, its yielding and ultimate load both obviously superior to common welded joints.