Abstract: Based on similarity criteria of the temperature field,the similar conditions in the HGEN heat source model were set up and deduced.By use of the conditions,the temperature field,displacement field and stress field of the butt welding and fillet welding were simulated and analyzed,comparatively.Numerical results show that the errors in temperature,displacement and stress field in the similarity model are quite small with those of original model,which are only 3.7%,4.7%,3.8%.Besides, the welding residual stress and deformation of box structure were simulated,and the welding residual stress variation and deformation change curve with distance of the similar box structure was obtained.The error between the simulated deformation and experimental measurement is only 9.8%,which furthermore certifies the correction of similar conditions of the HGEN heat source model.