Abstract: The operation of shield tunnels typically lasts for 50~100 years. Recently, the Structural Health Monitoring System (SHMS) for shield tunnels has received much attention with more and more river-crossing deep-buried large-diameter long-distance shield tunnels being built in China. Based on a comprehensive review of the current SHMS for tunnels, and considering the design characteristics of shield tunnels, a clear definition is put forward for a Shield Tunnel SHMS (STSHMS). A STSHMS is a data acquisition, management and analysis system for shield tunnels, which uses long-term monitoring techniques, data analysis and mechanical analysis, with the aims to verify key design parameters and index, assess and evaluate structure performance and provide a basis for allocating Maintenance and Rehabilitation (M&R) resources. The STSHMS comprises three subsystems, i.e., a data acquisitiontransmission-storage subsystem, a data integration- visualization-warning subsystem, and a data analysis-assessment subsystem. The main contents and design approach of each sub-system are introduced, with a discussion of key issues of determination of monitoring items and locations, sensor selection, data integration, visualization, development of health assessment methods and the relationship with M&R, as well as the engineering practice of developing STSHMS in the Shanghai Yangtze River Tunnel Project. Finally, some concrete suggestions are provided for the design and implementation of STSHMS.