模型是DSS的核心部分， “经济发展与环境保护辅助决策支持系统”从经济决策行为所带来的经济状态变化对环境的影响为出发点， 研究了环境与经济相互关系状态的评价、分析及优化决策三大类模型， 并对主要模型、系统结构和模型运行过程进行了介绍。

Model system is the most important part of the DSS. The key point of Decision Support System for Economic Development and Environmental Protection is that the change of the environment is caused by the economic development. Analyses show that different policy systems bring different economic state, and different economic states result in different environmental state characters. Firstly, according to the principle, the model system shows the policy classification including object layer, decision layer and state layer. Secondly, the logic model between economic development and environmental protection is introduced. For the more, the main models are put forward on three levels including assessment model, analysis model and decision model. At the end of the paper, the structure of the DSS and the running process of the model are displayed.