Abstract: According to the requirement proposed by the Ministry of Water Resources that "over-standard flood will not cause chaos, and below-standard flood will not cause accidents", the Changjiang Water Resources Commission organized an over-standard flood prevention plan for the Yangtze River Basin of 2020 before the main flood season. In this plan, over-all considerations were given for flood prevention preparation, hydrological monitoring and forecasting, water conservancy project operation, engineering inspection and defense, disasters rescue and relief, personnel rescue and placement, which provided a strong support for the flood prevention in the Yangtze River Basin in 2020. Generally, over-standard flood in a river basin has the characteristics of extensive influence, serious disaster results and difficult defense. Based on systematical summarizing the plan preparation thoughts, some in-depth analysis of the key issues during the prevention plan compiling were carried out in this paper, including the concept, flood control node, flood standard, prevention target and prevention measures of over-standard flood, etc. Furthermore, some suggestions were put forward in order to further improve the operability of the plan.