The current water quality of Luopengwan section cannot reach the standard stably. In order to further improve the success rate of national assessment of water quality andcontinuously improve the water environment quality,the research on Luopengwan section of water quality and water environmental capacity calculation of Xu River was carried out. According to the analysis of present situation of hydrology,water quality and pollution source data,the reasons for exceeding the water quality standard of Luopengwa...