Abstract: To solve the problem of dynamical safety risk assessment and management during the construction period of an underground project, a risk index system was developed based on the analysis of safety risks at this stage. By considering close-spaced impact, a method to assess the safety risks was given, and the risk acceptance criteria for underground engineering was proposed. A risk management system based on WebGIS was built for a tunnel project along the Beijing-Shijiazhuang passenger railway line. This system has functions such as the real-time collections of information on monitoring data, expert assessment and access control system, the dynamic assessment and alerting of the safety risks and the raising of corresponding suggestions. Practical application and monitoring result indicates that the system can lower safety risk at the construction stage of an underground project and reduce the possibility of accidents happening efficiently.