Abstract: During the 13th Five-Year Plan period, the total phosphorus concentration in the main stream of the Yangtze River met the water quality standard, but the total phosphorus in the middle and upper reaches of tributaries and lakes in the middle and lower reaches of the Yangtze River has exceeded the standard obviously. The establishment and operation of the cascade reservoirs in the upper reaches of the Yangtze River changed the water and sediment conditions, resulting in a significant reduction of particulate phosphorus but an increase of dissolved phosphorus. The change of phosphorus transport patterns aggravated the total phosphorus problem in the middle and lower reaches, and produced a series of ecological and environmental effects. The input of phosphorus from upstream tributaries accelerated the accumulation of phosphorus in cascade reservoirs and increased the potential risk of water pollution and eutrophication. The reduction of particulate phosphorus in the middle and downstream changed the distribution of phosphorus form and increased environmental vulnerability. The excessive phosphorus levels in shallow lakes drove the internal circulation mechanism and accelerated the eutrophication process. The steep decrease of phosphorus flux from the Yangtze River to the sea would have a profound impact on the ecological environment of the coastal waters. In view of the total phosphorus problem in the Yangtze River, it is suggested that the input source control should be carried out first, such as strengthening the control of the "three phosphorus" problem, curbing the trend of exceeding the standard of phosphorus in key tributaries in the middle and upper reaches of the Yangtze River. Meanwhile, the construction of urban sewage collection and treatment infrastructure should be accelerated, agricultural non-point source control and lake ecological restoration system should be improved, and phosphorus emission sources in the middle and lower reaches should be controlled. Secondly, it is suggested to implement joint sediment regulation of upstream cascade reservoirs to reduce siltation in the reservoir, increase sediment transport capacity, and increase particulate phosphorus level and phosphorus flux in the middle and lower reaches of the reservoir. Finally, it is suggested to improve the standard method of total phosphorus monitoring, strengthen the monitoring of total phosphorus in the whole sediment, and pay equal attention to the monitoring of phosphorus concentration and flux, so as to provide scientific and systematic data support for the control of total phosphorus in the Yangtze River.