The purpose of the present paper is to explore the effects of the rise and fall of the national situation before and after the An-Shih Rebellion on the ups and downs of the great families' power in the Tang Dynasty. Judging from the frequent-seen family-protection attitudes among the great families in the Middle Age, we may observe that these families were severely suffered by the wars and chaos no matter whether they moved to Wu-Yueh in the south, Sha-Sho in the north, Shu in the south-west, or hibernated or even stayed where they were. Some of the great families vanished from then on. Some recuperated and participated in politics and took up official duties once again after the An-Shih Rebellion. These all resulted in the social mobile phenomena of the great families. Among the above-mentioned four ways that the great families used to deal with the wars and chaos during the An-Shih Rebellion, the phenomena of moving towards Wu-Yueh in the south is worth paying greatest attention to. It not only caused “The Prosperity of the Literary Style in the South” and the large growth of the great talents in the south but further led to the movement of the Chinese social, economical, and cultural center to the south. It was a significant turning point for the rise in the south and the fall in the north in Chinese history.