Abstract: One-dimensional river quality system dynamics model is applied to the water quality simulation and conceptual GIS-SD frame is constructed.Based on ComGIS and system dynamics model,the experimental system of water quality simulation in water pollution accident was developed.The Songhua River water pollution accident was taken as an example.The spatio-temporal change of nitrobenzene concentration is dynamically simulated.The results show that the simulation of spatio-temporal distribution of pollutant in water pollution accident,model regulation,scenario analysis can be realized.