Abstract: Using the three-dimensional finite element method,the residual deformation of joints obtained with the AH36 steel plate with thickness of 6 mm under different welding conditions was studied in this paper.The numerical simulation results showed that the longitudinal distortion and the angular distortion changed dramatically.As to different welding methods,the deformation was small when the unique CO₂ gas arc welding was used,while large deformation was found when the CO₂ arc and SAW were combined together.The residual deformation was controlled effectively by water cooling,especially for angular deformation with the unique CO₂ gas arc welding.To verify the finite element simulation results,an experiment using the same parameters was done.With some error,the experimental results were consistent with the numerical results,indicating that the welding deformation in different welding conditions can be simulated with the three-dimensional finite element method.