The engineering cost control is crucial in the construction industry, and structural optimization is a key step for the project cost control.Traditional structural optimization always pays too much attention on structural reliability, including the safety, applicability and durability of the structure, whose target is too single and focused, which could hardly consider the overall collaboration of structural optimization with other professionals or during the construction stage.The BIM technology possesses the advantages of visualization, parameterization and coordination, which is able to reduce errors, improve efficiency and achieve standardized design.By using BIM-related platform, this paper firstly establishes an architectural and structural model for a project case study.In the premise of ensuring structural reliability, the influences of factors including reinforcement amount, cast-in-place concrete template volume, formwork area, artificial consumption, and etc.of the project are overall considered to put forward the final structure scheme.Different project construction costs of all these structural schemes are also analyzed to propose a BIM-based structure optimization process.The result shows that by utilizing BIM technology, structural optimization is more effective with more reasonable layout scheme, lower project construction cost, and a more simplified optimization design process, which helps the project participants to control the cost of the project more directly.