Abstract: A visco-elastic-plastic constitutive model for welding of A7N01-T6 aluminum alloy was established,considering the welding thermal temperature and deformation history. The model used elastic-mixed hardening plastic and creep equation to describe the strain hardening at low temperatures and strain softening at high temperatures,respectively. And it was applied for finite element numerical simulation of the welding process. Based on the established constitutive model,the welding residual stress and strain agreed well with the theoretical results. Compared to the ideal temperature dependent elastic-plastic model, strain hardening at low temperatures and strain softening at high temperatures had combined effect that led to invariable welding residual stress. Due to strain softening at high temperatures,the overall longitudinal residual compressive plastic strain and the maximum deformation of welding sheet were much larger using the newly proposed model.