Based on disaster system theory, a simplified method to disaster risk assessment was developed by combining hazard risk assessment and potential vulnerability assessment. Flood risks of Metropolises in China were assessed and studied on two different scales. The result indicated that, the spatial pattern of flood risk shaped a circle-liked structure and the risk index dropped gradually from the center of Metropolitan Regions to the outer edge zone. Flood risks of Metropolises in the south are significantly higher than those in the north. Ranked by flood risk from high to low, Metropolises respectively referred to Yangtze River Delta, Pearl River Delta, Middle Reach of Yangtze River, Beijing-Tianjin-Tangsan, Jilin-Heilongjiang, China North Plain, Chengdu-Chongqing, Central Section of Liaoning and Shangdong Peninsula. Based on the flood risk analysis above, relevant energy management system was put forward as a safety protection strategy for flood alleviation in these areas. It is suggested detection-forecasting-warning, emergency protocol compiling, and regionalization-planning should be contained in the system.
