Four states of transmission network single-line power flow diagram， such as historic， present， near future， future， are put forward in accordance with four states in life cycle: planning， construction， operation/refurbishment and retirement of main equipments in electric power grid. The automatic generated transmission network single-line power flow diagram based on information of power grid in near future state or covering present annual business plan， is recommended for real dispatching large screen use， which can provide a steady structure of power grid layout and routing in certain period， which is in favor of keeping of familiar with large screen diagram for dispatchers and helping their dispatching business. In order to provide a necessary operating system for intelligent dispatch automation system， an integration scheme and an operation procedure， with a great degree of automation， are also suggested. Four types of diagram for each states of power flow diagram， are defined such as: geographic information based connection， layout， routing and real-time integrated， in which the latter three items will again be divided according to its pre-layout depending on supply area or district.The system functions and key techniques of data import interface are also discussed. This paper with references［1-2］ provides a total solution for automatic generation of transmission network single-line power flow diagram for dispatching large screen display. The system has been applied to Zhejiang power dispatching center and provides conditions for achieving intelligent dispatch automation.