Abstract: In this paper, a new material model with considering softening phenomena in aluminum alloy welded joint was developed to accurately calculate welding residual stress and deformation. In the current study, the welding residual stress and distortion in a 6061 aluminum alloy bead-on joint performed by TIG welding process was simulated by using the developed computational approach. Meanwhile, the out-of-plane deformations were measured by experiment, and the measurements were used to verify the numerical results. The numerical results show that softening effect has a significant influence on longitudinal residual stress, which has a limited influence on transverse residual stress. It seems that the softening effect could only influence on welding deformation.