In 618, Emperor Gaozu of Tang overthrew the Sui dynasty and established the Tang dynasty. Qiu He first submitted to Xiao Xian's empire in 618, then to the Tang emperor in 622, incorporating northern Vietnam into the Tang dynasty.^[95] A local ruler of Jiuzhen (today's Thanh Hóa), Lê Ngọc, stayed loyal to Xiao Xian and fought against the Tang for another three years.

In 627, Emperor Taizong launched an administrative reform which reduced the number of provinces. In 679, Jiaozhou province was replaced with the Protectorate General to Pacify the South (Annan Duhufu). This administrative unit was used by the Tang to govern non-Chinese populations on the frontiers, similar to the Protectorate General to Pacify the West in Central Asia and the Protectorate General to Pacify the East in northern Korea.^[96] Every four years, the "southern selection" would choose aboriginal chiefs to be appointed to fill positions of the fifth degree and above. Taxation was more moderate than within the empire proper; the harvest tax was one-half the standard rate, an acknowledgement of the political problems inherent in ruling a non-Chinese population.^[97] Native girls of Vietnam: Tais, Viets and others were also targeted by the slave traders.^[98] The women of Viet tribes were most likely used as everyday household slaves and handmaidens during most of the Tang.^[99]

For the first time since the Han dynasty, Chinese schools were built, and dykes were constructed to protect the capital city of Songping (later Đại La). The Red River delta was the largest agricultural plain in the empire's south, with roads connecting Champa and Zhenla to the south and the southwest, and sea routes connected to the Indian Ocean.^[100] Buddhism flourished in Annan, although the Tang's official religion was Daoism. At least 6 monks from northern Vietnam traveled to China, Srivijaya, India and Sri Lanka during the Tang period.^[101] Very few natives engaged in the Confucian scholarship and civil service examination.^[102]