The whole framework of coordination theory of electric power system optimal dispatch considering security and economics is established， and the coordinative dispatching mechanism and model at 7 aspects of space scale， time scale， power production link， controlled object， security and stable control strategy， optimized goal and open impartial equitable dispatch are presented. On the space and time scale， the coordinative optimal dispatching model and algorithm of“pre-decision making（pre-arrangement） and declaring from bottom to top， decision making from top to bottom， multi-level optimal coordination and refining level by level” are proposed. In this model， the mutual optimal coordination of each level of optimal dispatching schedule between the current time scale， the previous and next time scale are considered， and the optimal arrangement of resources in the nationwide scale can be realized. In power production link， the energy-conservation power generation arrangement principle and dispatching pattern based on market mechanism are proposed.