The invention provides an active scheduled power flow adjusting method and device based on grid model expansion. The method comprises the following steps: calculating sensitivity of line nodes of a power grid in the current scheduling area according to data and system frequency response characteristics of a power grid topology model; performing equivalent calculation on tie lines between the current scheduling area and a high-level scheduling area according to the sensitivity, local scheduling planning data of the current scheduling area as well as power grid topology model data and unit planning data of the high-level scheduling area, and setting boundary parameters of the power grid topology model in the current scheduling area; adjusting active scheduled power flow of the current scheduling area according to the local scheduling planning data, the power grid topology model data and the unit planning data of the high-level scheduling area, the sensitivity and the power grid topology model subjected to boundary parameter setting in the current scheduling area. The accuracy of scheduled power flow calculation is improved with the method.