Transmission section is the weakness on whole power system, so the identification and control of transmission section has great influence on system safety and stability.Due to the lack of top-level design, grid dispatching operation control has the integrated problems including transmission section identification and maximum power transfer computing, etc. This paper researches grid dispatching operation control system and its development based on transmission section control. It studies the mathematical model based on dichotomy, computes the maximum power transfer of the transmission section and develops the operation system by taking section control as a core. Mathematical model of dichotomy is introduced and the operation system based on transmission section control is constructed. Key technologies of supporting transmission section control are discussed. The significant effect of the proposed system is proved through applying it in a reginal grid more than a year.