Taking a 220 t electric wheel dump truck as the research object, a finite element model has been established, followed by a finite element analysis of six working conditions of the dump truck carriage: full load stationary, full load turning, full load braking, full load turning braking, full load constant speed, and full load lifting. Based on the Optimization module, the size of the carriage structure is optimized, with the thickness of the dump truck carriage plate as the design variable so as to minimize the weight of the carriage as much as possible while ensuring that the structural stress meets the design requirements. Thus the overall mass of the final carriage decreases by 22.8%, achieving the goal of lightweight design for the carriage.