Abstract: In field engineering,experienced model all have their own scope of application,and period of effectiveness.These are determined by the selection of parameter and factor.The BP arithmetic mixed with momentum factor overcomes the weakness of pure BP arithmetic,and it is by the using of the knowledge speculation or deduction.The above-mentioned idea was embodied in the software of "Single Watershed and Diversified Reservoir Control System".A functional approximation was made by using MATLAB and C++.It automatically adjust the parameter of "New Anjiang model" to fit the different situation of different reservoir.So the parameter of model will change with the transformation of the environment,and greatly improve the flexibility of the model and the popularity of the software product.