Abstract: After electron beam welding, it is difficult to correct deformation of large and multi-weld thin-walled aerospace module components. The simulation calculation can predict deformation trend and optimize welding process to obtain the minimum deformation. Simulation was used to predict deformation trends and optimize welding process to minimize post-weld deformation. The study involved numerical simulation of welding process on an aluminum aeronautical module. After establishing and verifying finite element model using a flat plate structure, aero-module was then modeled. The investigation focused on influence of welding sequence and welding parameters on the maximum deformation after welding, as well as deformation trend of the module. The findings indicated that the module’s deformation trend was downward and that prioritizing the welding of the two longitudinal seams led to a larger deformation. And greater heat input resulted in increased post-weld deformation. When adhering to the demand for a 6mm depth of fusion, the minimum welding deformation (0.35 mm) could be achieved by high welding speed (35 mm/s) and low power (5 400 W). The paper aims to provide a basis for optimizing welding parameters for thin-walled, large-scale aero-module structures.