Abstract: Using finite element methods to carry on a dynamic simulation of a welding process of spherical tank girth welds and the plate, from which the changes in the temperature field and the laws of welding residual stress distribution in the welding process of the spherical tank were analyzed. It was mainly concluded that welding heat-affected zone was very small, and the residual welding stress in spherical tank girth welds were functions of meridional and radial coordinate, and the zonal residual welding stress was larger than the meridional stress, and the maximum value of 2-D stress was in the heat-affected zone, and the value of the maximum stress exceeded the yield stress, which was a cause of the spherical tank defects. The residual welding stress in the plate welded joint was tested by X-ray method, and the testing results were compared with the numerical simulation results. The results matched which means the simulation method is feasible.