Abstract: This article introduces a research on the control process of welding deformation in the manufacturing process of railway freight car bottom door structural components. By optimizing the welding seam structure of the bottom door, selecting appropriate welding current, welding voltage, and welding speed, and combining with the welding deformation trend of the aluminum alloy bottom door, a targeted rigid fixing and prefabricated anti deformation plan is formulated to achieve the goal of eliminating the need for secondary adjustment and shaping after the welding of the aluminum alloy structural components, avoiding the problem of weld cracking caused by mechanical adjustment due to inadequate flatness of the aluminum alloy structural components, ensuring the product quality of the aluminum alloy bottom door composition, and eliminating the secondary adjustment process to improve production efficiency and create higher benefits for the company.