The balance shaft bracket is a key component of the balance suspension of heavy commercial vehicles, and the component with the largest weight proportion in the balance suspension assembly. In response to the problems of heavy weight and poor manufacturing process of the existing balance shaft bracket product for a heavy commercial vehicle, it is urgently needed to develop a lightweight and well-manufactured balance shaft bracket product. Based on the ANSYS Workbench platform, a finite element model for the balance shaft bracket of a heavy commercial vehicle was established. Strength analysis of the balance shaft bracket was conducted under three typical serving conditions. Then, a lightweight design of the balance shaft bracket was carried out by using the topology optimization technology based on the variable density method. According to the structural topology optimization result, the model of the balance shaft bracket was reconstructed, and the strength of the optimized structure was verified. The results show that the weight of the optimized structure decreases by 46.5%, and the strength meets the usage requirements. Finally, trial production of the balance shaft bracket with the optimized structure was conducted by using the sand-faced iron mould casting process. A good castability of the optimized structure is obtained and the casting quality meets the requirements.