Abstract: In response to the national strategy of building a transportation powerhouse and to accommodate the continuously increasing traffic demand on expressways, Building Information Modeling (BIM) technology has emerged as an indispensable technical enabler for highway reconstruction and expansion projects, facilitating high-quality construction and intelligent operation and maintenance management. Addressing the practical requirements of highway bridge reconstruction and in conjunction with the current state of domestic coding standards, this paper proposes a BIM classification and coding framework specifically tailored for such projects. A taxonomy for the organizational structure of reconstruction and expansion road and bridge models is further established. Leveraging the widening and reconstruction project of the Jialiu section of the G15 Shenhai Expressway, the applied research and practical implementation of BIM model coding digitalization are presented.