分析了复杂性定义与特征，揭示复杂性的主、客体本质。指出水资源系统也具有主、客体本质，复杂性是水资源系统的一个重要特征。结合复杂适应系统对涉及到经济、环境、人文和水资源规划等多方面的水资源系统进行分析研究。将水资源系统看成是由若干个相对独立的有适应性的个体所组成的一个有层次的网络体系，用定量与定性相结合的方式得到系统的演化规律。建立流域级的水资源复杂适应性系统模型对于研究水资源管理和维持生态平衡等都能起到直接的推动作用。

Based on the definition and characteristics of Complexity, it's revealed that the water resources system, like Complexity, has the subject-object essence. The water resources system in terms of economy, environment, humanity, water planning was analyzed. It is regarded as an hierarchical network consisting independent adaptive individuals. Regularity of the system's evolution was obtained through quantitative and qualitative approaches. To establish a complex adaptive system (CAS) of water resources in a river-basin-level will directly promote water resources management and eco-balance. 