Abstract: In response to the lightweight design requirements of the bucket arm of a wheel loader, firstly completes the definition of material parameters, boundary constraints and load Settings, and conducts the initial analysis. Secondly, based on the topological optimization theory, with the goal of maximizing stiffness, combined with constraints such as mass fraction and bidirectional drawing, the variable density method is used to optimize the material distribution of the bucket rod. And then, the topological optimization results were transformed into a solid model through geometric reconstruction technology. After strength verification, the maximum stress of the optimized boom was within the safe range, the minimum safety factor met the engineering requirements, and the mass was significantly reduced compared with the initial state. Research shows that the “topological optimization-geometric reconstruction” technical system can achieve efficient weight reduction while ensuring structural strength, providing a complete technical path integrating material distribution optimization and manufacturability design for the lightweight design of core load-bearing components of construction machinery. It has reference value for promoting the development of lightweight technology in construction machinery.