The invention relates to a multi-level multi-region collaborative control load shedding online simulation modeling method and a multi-level multi-region collaborative control load shedding online simulation modeling system. The multi-level multi-region collaborative control load shedding online simulation modeling method comprises the steps of: respectively modeling multi-level emergency load shedding collaborative decisions of a plurality of regions to form a plurality of multi-level load shedding collaborative control strategy models; respectively marking the multi-level load shedding collaborative control strategy models by using key words, customizing priorities for the multi-level load shedding collaborative control strategy models, and combining the marked multi-level load shedding collaborative control strategy models; and performing collaborative operation control on the combined multi-level load shedding collaborative control strategy model, so as to exchange information. Themulti-level multi-region collaborative control load shedding online simulation modeling method and the multi-level multi-region collaborative control load shedding online simulation modeling system are conductive to ensure stable operation of a power grid.