Abstract: The mathematical models and Geographical Information System (GIS) are the powerful ap-proaches and technical supports for the researches on urban water pollution. This paper pointed out that CD the regional environmental elements are of great importance when a water quality model is applied to a specific water body, therefore, the spatial analysis for the elements of the water environment, including the pollution source analysis, is of great significance, and GIS can be used as a pre-processor for solving this problem with its powerful function of spatial analysis; (2) the results from the water quality model can be visualized and showed in GIS, which become a postprocessor of the model. Regarding Suzhou Creek, which has been being seriously polluted in Shanghai City, as an example and based on a large amount of data and materials from pollu-tion source survey, this paper first developed the Water Environment Information System for Suzhou Creek based on ArcView, which formed the basis of the analysis of pollution sources and water quality simulation, and then simulated the characteristics of water quality variation of Suzhou Creek with the method of the integration of water quality model (WASP4) and GIS (Ar-cView). The results of the simulation are visualized in the ArcView windows through a data transformation program.At last. we discussed the characteristics of time and spatial variation of water quality for Suzhou Creek, and verified that there is a "Pollution Belt" in the course. The reciprocation characteristics of this "Pollution Belt" is also discussed.Based on the research work above, we believe that the integration of the environmental mathematical model and GIS is of great significance and will have bright future.

Key words: numerical simulation of water quality, GIS, Suzhou Creek, pollution belt