In view of the huge losses of water resources and economy caused by the frequent occurrence of sudden water pollution events in urban rivers, Hartree closed-loop river and lake water quality early warning method is proposed. Through the disposal process of incident occurrence, traceability, early warning and investigation, prediction and analysis, emergency treatment and restoration, and implementing the measures of monitoring and early warning, water quality inspection, river chief App, model prediction, emergency repair and alarm relief, a fast response and accident handling method based on water pollution traceability is proposed. Taking the Jinchuan River system in Nanjing as an example, the process of pollutant tracing, response and accident treatment after water pollution emergencies is studied. Based on the calculation of the coupling model, the correlation between the quantity of water transferred and the duration of water quality exceeding the standard is obtained through the comparison of the concentration fields of different water transferred quantities with or without using the Hartree closed-loop river and lake water quality early warning method. The efficiency of handling such events is improved from the perspective of method utility.