Our research employs the concept of building information modelling (BIM) in environmental impact assessment for urban deep excavation projects. BIM is a relatively new technology that facilitates better information integration and management. Many engineering companies employ BIM for information integration, visualization, and parametric design, to reduce both the duplication of work and the complexity of interface integration. In this research, a 3D-building model, an excavation model, environmental conditions, the results of ground surface settlement analysis, and measurement and monitoring data, were integrated into our system to assist construction project teams to execute environmental impact assessment accurately. The risks and issues affecting safety of excavation and nearby structures might be recognized earlier through conveying information visually in this system. Construction project teams can then handle them immediately. The implementation of the system was carried out in the MicroStation Visual Basic for Applications (MVBA) environment. The Bentley MicroStation supports visualization of the 3D-model and provides some capabilities for 3D-object manipulation and information query.