Abstract: The numerical models of 2A12 aluminum alloy T-circular pipe joints with arc and laser welding stresses were established, the temporal and spatial evolution of its temperature, stress and strain fields were discussed, and the deformation and residual stress distribution law was obtained. It is found that laser welding produces lower heat input due to faster welding speed and smaller heating area, and laser welding has lower maximum residual stress and smaller high residual stress distribution area compared with arc welding, which results in lower deformation, in which the transverse deformation and flexural deformation in the weld direction are reduced by 71.60% and 57.92%, respectively.