With the formation of national interconnected power systems， the grid structure and operation mode will become increasingly complicated. Currently， in a dispatching center， an accurate power system model is developed only for its control area while the external power grid is dealt with just in an equivalent or inaccurate manner. This traditional practice cannot meet the requirements of the development of interconnected power systems. Based on the IEC 61970 standard and E form， a hierarchical and decomposition and space-time coordination modeling system is studied for interconnected power systems. In the modeling system， some technologies are combined， such as version management， model mergence/separation， network equivalent and so on， so that space-time coordination modeling in multi-dispatch centers of interconnected power systems can be realized. The modeling system provides a technical means of internal and multi-levels coordination for dispatching centers， in addition to information infrastructure and technical support for the real-time monitoring and control as well as an online security and stability analysis of interconnected power systems.