There is a phenomenon that the sentiments of the poets in every Chinese dynasty were affected by the moving of the frontier fortress. And this article takes the Tang Fortress and its poems as an example exploring the relationship between them. The emotional change of the poets is closely related to the moving of Tang frontier, but they did not synchronize with each other. In the early Tang, the Government implemented the System of Autonomous Region; therefore, the enlargement of the territory was not written in the poems. In the high Tang, the territory had shrunk compared to the early Tang, but the western region was in the government’s direct charge and some intellectuals went there as the managers; therefore the fortress poems flourished. After the An-shih’s Rebellion, with the inward moving of the frontier, the poems became bleak and sad in the middle and late Tang.