Abstract: In the early stages of the An Shi Rebellion,Emperor Suzong's journey was the result of repeated decision-making and constant adjustments to his route based on a continuous flow of information.Emperor Xuanzong ordered generals from the Hexi and Longyou regions to take command of the defense of Tongguan while deploying the main forces of the Shuofang Army to attack Heshuo.This strategic arrangement placed the Hexi and Longyou in a politically and militarily pivotal position during the early stages of the An Lushan Rebellion.Unlike Emperor Xuanzong,who sought to maintain the northwestern border defense system,Emperor Suzong,in order to quell the rebellion,continuously summoned frontier troops for reinforcements.In the campaigns to recapture the two capitals,the Hexi and Longyou forces suffered successive defeats,while the Shuofang Army,along with the Anxi and Beiting armies,gradually assumed a more significant military role.The actions of Emperor Suzong and the transformation of the northwestern military governors'power illustrate the process of the restructuring of the Tang Dynasty's state power under the impact of the rebellion.