From the view point of systems science,the scientific methodology should go beyond reductionism,to adopt systematic methodology.As the theoretical foundation of systems science,systematology should be developed based on the deep research on the emergent properties of complex systems.Emergent property is an important topic in complexity research.It concerns about the emerging of global spatialtemporal structure and function in complex systems.It is believed that the selforganization of individual agent through nonlinear interaction is crucial to the emergence of global collective behavior at macroscopic level.The basic approach for understanding complexity is to investigate the universal laws that determine the emergent behaviors in variant complex systems.Complex networks,as the basic approach to characterize the interaction among components of the systems,are the basis for modeling the systems and understanding the properties and functions of the system.