Implementation of energy-saving generation dispatching will have an impact on the power grid security and stability. The sorting principle and the change of power flow after the implementation of energy-saving generation dispatching are discussed， and the security and stability of southern power grid of Hebei Province under the energy-saving scheduling model and the traditional scheduling model are compared， then a sorting method considering unit zonal classification which is applied for the energy-saving generation dispatching is proposed. In this method， units are sorted within individual zones in accordance with the generation priority table of energy-saving generation dispatching. According to the zonal load ratio of the entire grid， the zonal unit output is determined. The computation results show that the proposed sorting method can effectively improve the transient stability and reduce the power loss over the grid in southern Hebei Province.