Abstract: Considering the lack of the sufficient measured data of the cities' river net and unsat is factory simulation speed of the hydrodynamic model,an intelligence model for river net is presented in this paper combining the hydrodynamic model with genetic algorithm and artificial neural networks. The information is supplied by the hydrodynamic model and the original weights of artificial neural networks are optimized by the genetic algorithm. The model is used to simulate the river net of Pudong New District in Shanghai Sound agreement is obtained between the results of intelligence model and those of hydrody namic model. It shows that the accuracy of intelligence model for river net is close to that of the numerical model,and the in telligence model has an advantage of good real time performanc. It provides a good technique for forecasting water level and the similar problems.