Abstract: An efficient enhanced moving heat source model was developed based on the MSC. Marc finite element software platform. The thermo-elastic-plastic finite element method, along with the enhanced moving heat source model, was employed to numerically simulate the welding deformation of a large-scale long straight rolling stock structure measuring 13832 mm in length. Simultaneously, the welding deformation of the long and straight structure was measured experimentally and compared to the numerical simulation results. This comparison verified the accuracy and feasibility of the developed finite element calculation model for welding deformation in such structures. Subsequently, the developed computational method was used to investigate the impact of different welding sequences on the welding deformation of large long straight structures in rolling stock. The calculation results demonstrate that the welding sequence significantly affects both the mode and magnitude of welding deformation. By adjusting the welding sequence, substantial reduction in welding deformation can be achieved. This study provides guidance for the production of large long straight structures and reduces the process development cycle.