Abstract: The chassis frame of emergency power supply vehicles, which serves as the core support structure, is susceptible to deformation issues due to its complex assembly and intricate welding processes. Such deformations can negatively impact the vehicle's assembly precision and operational performance. This study performs a finite element simulation analysis on the chassis frame of emergency power supply vehicles, utilizing the thermal elastic-plastic method and the inherent strain method. We examined six welding schemes, considering both the assembly sequence of components and the welding sequence of joints, to assess the influence of different welding schemes on the structural welding deformation of the chassis frame. The results demonstrate that the simulated local joint pool morphology aligns closely with the experimental pool morphology. The distribution patterns of welding deformation for the chassis frame structure across various welding schemes are relatively consistent, with the largest deformation occurring in the central beam and the end beam of the chassis frame. The assembly sequence of components and the welding sequence of joints have a negligible effect on the deformation of the outer longitudinal beam, while a significant change is noted in the internal beams. Implementing assembly scheme 1 and sequence scheme 3 results in the smallest welding deformation.