Abstract: In1990s, the dams of hydropower stations have made great flood control benefit during several extreme floods. Meanwhile, abnormal phenomenon occurring many times of less reservoir inflow but high water level over dam imperiled dam and downstream hugely. Therefore, concept of flood control should be changed from controlling to managing, founding a set of system of flood control and disaster reduction with the whole people participating in, making scientific decision reasonably to avoid the risk of small flood but high water level and prevent overflow and dam failure event for ensuring national economy in sustainable development.