Abstract: Identifying such earthquake-damaged risk elements is the foundation to the safety evaluation and scientific prevention for underground engineering. With the application of system theory, the comprehensive risk system was carried into structure decomposition and element integration for earthquake-damaged underground engineering, which erected the three supportting formal structure description with task, event and element, and took the multi risk elements into all consideration. From the geological conditions, topography and geomorphology, engineering effect, environmental conditions, monitoring performance and other point of view, the risk element was respectively interpretted; the risk logical association and mechanism was explored between the disaster causing elements and the hazard bearing elements for earthquake-damaged underground engineering. Finally, the concept system and methodological framework was erected for earthquake-damaged risk analysis science, which provides the basis for exploring the essential elements of the earthquake-damaged risk system, and carrying on the comprehensive integrated system analysis and assessment for underground engineering.