In this study, a decision support system for system dynamics modeling is designed. The intelligent part of the system is composed of a knowledge base, a data base and an inference engine. The function part of the system is composed of some modules for model construction, model generation, model simulation, model interpretation, model management, and PD interface. The proposed system is a production system written in PROLOG, and it can join up with the professional Dynamo plus software by means of the PD interface. Whole process from modeling to simulation can be realized by the support of the system. An application example is given in this paper.