This article investigates when and how many Baekje people emigrated to Tang China and what kind of activities they conducted there. There are four specific times when they migrated to Tang as follows: when their country collapsed in 660, when Baekje Restoration Movement failed in 664, when Goguryeo kingdom ruined in 668, and when Ungjin Commandery established in the former Baekje territory abolished in 675.
The number of people that left Baekje for Tang in 660 was about 12.000~13.000 including King Uija(義慈王), the last king of Baekje kingdom, the crown prince Buyeo Yung(扶餘陵), princes, royal family members, vassals and the people. We do not know how many emigrated to Tang in 664, 668 and 675 because of lack of related historical records. It is likely that more people migrated to China in 675 than in 664. Royal household and high ranked aristocrats were sent to Luoyang(洛陽) and Changan(長安) and lower class of aristocrats and the people to Yanzhou(?州) and Xuzhou(徐州). When Ungjin Commandery(態津都督府) was moved to Liaodong(遼東), the Baekje people who lived in Yanzhou and Xuzhou were sent to Jianan(建安).
King Uija died as soon as he arrived in Tang but Buyeo Yung and royal family in direct line of him were in charge of control their people living in Ungjin Commandery and in Tang. Some of royal family members were famous in China by joining wars with Turk(突厥) and Tibet(吐藩) as generals. Some strengthened their position within China by marrying imperial relatives or influential families.
Descendents of the families that were on China side such as those of Heukchi Sangji(黑齒常之, 630-689) and Ye Shikjin(?寔進) when Baekje kingdom collapsed and Restoration Movement was quelled by the Silla-Tang allied forces settled down in Luoyang and Changan. They were taken to control over the former Baekje people as government officials in Ungjin Commandery or had good wars with Turk and Tibet as Tang dynasty generals. Satachungui(沙?忠義) played an active part as a general and deeply involved in political strife in the Chinese Tang palace. Nan Wongyeong(難元慶) played a role as a retainer close to the emperor within the Secretariat(中書省, Zhongshu Sheng), one of the three departments of Tang dynasty.
The common people that were the greater part of Baekje emigrants to Tang China got family registers and were gradually assimilated into the Chinese community. However we do not know what kind of activities they conducted in China due to lack of related records. I expect that new materials on these people will be discovered.