In simulation or evaluation of composite systems, the choice and quantification of indexes are key contents. A new evaluation model was put forward to quantify the indexes weights of Eco-water network composite system by uniting AHP and entropy value method,the model avoided the subjective in using analytic hierarchy process (AHP) and partial in using entropy value method separately. That is the indexes weights were calculated by AHP and entropy value method respectively firstly, and then the weights were determined by according to comprehensive function. The alliance of AHP and entropy value method can be regarded as the combination of subjective and objective method. It reduced the error rate and false reject rate in the process of data classification and identification, compared with using AHP and entropy value method individually, the alliance method makes the results more objective and reasonable in the index quantification of Eco-water network composite system. Based on the ecology, water network data from 2008 to 2012 in Hebei province, the two sub-systems including ecology and water network system were analyzed, and the ten indexes weights of the composite system were calculated. It lays the foundation for coupling simulation, evaluation and management of the composite system.