Abstract:  Effectively identifying the priority pollutants of the water environment is an important aspect of constructing a coordinated water environment monitoring system in the Yangtze River Delta Integration Demonstration Zone. Entrophy Method and TOPSIS method were used to screen the priority pollutants from 80 specific pollutants other than basic monitoring items in “Surface Water Environmental Quality Standard” based on the quarterly 109 full-indicator monitoring data from 2017-2019 of the Taipu River, which is an important transboundary river in the integrated demonstration zone, with four evaluation indicators such as the frequency rate, spatial distribution, maximum occupancy rate and carcinogenicity .The results show that: (1) The risk of antimony is high; the risk of nickel, dichloromethane, and acrylamide is relatively high; the risk of cobalt, titanium, boron, sulfide, atrazine, microcystin-LR, 1,4-dichlorobenzene and chlorobenzene is average. (2) At present, the water administration and data management in Wujiang in Jiangsu, Jiashan in Zhejiang, and Qingpu in Shanghai are significantly different from the water environment co-governance goal of “unified standards, unified monitoring, and unified law enforcement”. (3) Based on the monitoring status of the demonstration area and the identification results of priority pollutants, this study puts forward some water monitoring recommendations for the Yangtze River Delta Integration Demonstration Zone from the perspectives of “improving monitoring indicators and information disclosure”, “improving coordinated monitoring and data sharing”, and “improving the integrated water environment early warning system”.