Abstract: Based on finite element analysis software MARC, the 3D numerical simulation on laser welding of "grooved-coat" structure was conducted.This research work concerned the application of hybrid heat source model of laser welding, the simplifications of the mechanical and thermal boundary conditions, the discussions on the computed results of temperature field and residual stress field, and that of the comparison between the shape and size of computed weld pool and the experimental results.The results of the comparisons show that the finite element model is reasonable.The effects of the welding sequences on the welding residual stresses and deformation of structure were investigated.The results show that different welding sequence can get the same distortion pattern, but their deformation have difference, and the distribution of the residual stress is different from each other.The deformation and the residual stress obtained with symmetrical welding from outer to inner is the lowest.