Abstract: Affected by the El Nino phenomenon, a long-duration and wide-ranging process of heavy rainfall occurred in the Yangtze River Basin in 2020. From July 3 to August 17, a total of 5 numbered floods occurred in the Yangtze River Basin. The flood process and characteristic change in the middle and lower reaches of the Yangtze River are directly related to the flood prevention safety of the Yangtze River Basin. According to the latest measured data, the flood process and characteristics of the middle and lower reaches of the Yangtze River during the 2020 flood season are analyzed, and the impact of the peak reduction of the Three Gorges Reservoir on the flood prevention of the middle and lower reaches of the Yangtze River has been preliminarily studied, and some new preliminary understandings have been obtained, which provides a basis and reference for further study of flood prevention in the middle and lower reaches of the Yangtze River.