Abstract: The production of dump truck carriage of engineering transport vehicles mainly uses welding process, and the welding deformation is the major factor affecting the quality of the carriage. In order to reduce the welding deformation of dump truck carriage, the maximum deformation position on dump truck carriage side, namely long channel steel weld position, was selected for numerical simulation. By applying Gauss thermal load and using thermal-structural coupling analysis, the stress distribution and deformation after welding were obtained. According to the actual production situation, the welding process was adjusted, and the "four-point fixed" scheme L and R were put forward. The two schemes were simulated and analyzed, and a scheme was selected. Finally, the experiment shows that the optimized scheme improves the whole quality and appearance of the carriage.