Based on the actual data provided by the “Southern Power Grid '1 +5' ancillary services assessment system (short for Southern network '1 +5' assessment system)”, this paper analyzes the hydro-thermal power plants' regulation conflicts existed in Yunnan Power Grid that is the AGC regulation pressure. According to the capacity calling rate's put forward and investigation, a suggestion of reasonable arrangement for AGC service amount is given. What's more, a unified management, coordination control strategy of the dispatching centre is proposed too, and a corresponding control system is established to realize this control idea. The proposed method and system also has a guiding significance to the dispatching operation in the other high ratio hydropower areas during wet season.