Due to fast urbanization of the city, underground structures such as subways have been widely used to reduce the impacts on aboveground activities and to increase the availability of space by going underground. Since these structures are often constructed in a crowd area of the city, accidents caused by them may easily result in serious damage to nearby structures and underground pipes, which, of cause would delay the whole project. Generally, ground settlement is taken as the major impact for adjacent environment and schedule. It is essential to monitor and evaluate the impacts during construction of underground structures, especially for underground excavation. To address these issues, the concept of Building Information Modeling (BIM) was employed in settlement monitoring and impact management for underground projects. BIM is a technology adopted to decrease the complexity and duplication of the work with a better capacity for information integration, visualization and sharing. In this research, an information model for settlement monitoring and impact management was established, and workflow for settlement monitoring and impact management based on this model was proposed. With the BIM-based construction management system developed before, 3D building model, nearby structure model, excavation schedule model, settlement analysis results and risk warning levels were integrated. By dynamically integrating actual progresses and monitoring data for settlement, possible risks and issues can be identified earlier through comparison between monitoring data and theoretical analysis results with effective visualization of information. Proximal structures and related excavation activities can also be highlighted, assisting project team to address the problem and adjust the schedule appropriately in time. Developed functionalities were tested in the excavation of Suzhouqiao station of line 16 in Beijing to validate their feasibility and effectiveness. Results illustrate that this system will give the users a comprehensive view of the project through better visualization, flexible tools are also provided to assist settlement monitoring and impact management.