中国环境科学 2022,42(5):2299~2304 China Environmental Science addition, Bayesian network topology analysis and heuristic search algorithm can quickly identify typical pollutant sources and their pollution contributions in the watershed. In this study, the monitoring data of Drinking Horse River Basin in Jilin Province from 2017 to 2020 were selected for the water quality analysis. Ammonia was a typical pollutant in the watershed; the three sections of Khao San Nan Lou, Khao San Bridge and Liu Zhen Tun were polluted by Yang Jia Weizi, Xin Li Cheng Dam and Zhuang Wa Yao Bridge respectively. 63% of the pollution in Khao San Lou came from Yangjia Weizi, 30% of the pollution in Khao San Qiao came from Xinlizheng Dam, and 75% of the pollution in Liu Zhen Tun came from Brick Wayao Bridge. This assessment method can be constructed to provide strong technical support for the tracing of water environment risk and pollution responsibility determination in the basin. Key words:water pollution;risk traceability;mutual information;Bayesian network;heuristic search;yinma river basin