Hakka is a very unique branch of the southern Han nationality, one of the important ethnic groups of the Han nationality, and the only ethnic group that is not named after the region. In Chinese mainland, Hakkas are mainly distributed in Meizhou, Heyuan, Huiyang and other counties in Guangdong, as well as Jiangxi, Sichuan and Guangxi. Hakka dialect, in particular, is an important part of the languages of these countries in Southeast Asia and other places. According to statistics, there are about 80 million Hakkas in the world, including about 50 million at home and 30 million abroad. Therefore, Hakka is one of the most widely distributed and far-reaching ethnic groups in the world.

Until now, the academic circles have not given an accurate explanation for this problem, and there are different opinions. But literally, "Hakkas" means "immigrants", which is very vivid, because since the Qin Shihuang period, Hakkas have always experienced six large-scale southward movements, countless small ones.

According to historical records, the Qin Shihuang period was the first large-scale migration of Hakkas to the south. After Qin Shihuang Ying Zheng unified China, he sent 600,000 troops across the country, from Fujian, Guangdong and Jiangxi to Xingning and Haifeng counties. Seven years later, Qin Shihuang sent another 500,000 people south to defend Wuling. After the national subjugation of the Qin Dynasty, two groups of Qin soldiers who went south stayed in the local area and became the first Hakkas.

The Yongjia Rebellion at the end of the Western Jin Dynasty and the Five Rebellions in the Eastern Jin Dynasty were the second large-scale southward migration of Hakkas. In order to avoid the devastation of war, some people in the Central Plains moved to the border areas of Fujian, Guangdong and Jiangxi.

The Huang Chao Uprising in the late Tang Dynasty was the third large-scale southward migration of Hakkas. During the Anshi Rebellion, the land in the Tang Dynasty was devastated, forcing a large number of people in the Central Plains to move south. At the end of Tang Dynasty, Huang Chao Uprising, a large number of Central Plains people moved south. But this is also the embryonic stage of Hakka dialect.

The southward crossing and the end of the Song Dynasty were the fourth large-scale southward migration of Hakkas. At the end of Song Dynasty, Hakkas took part in anti-Yuan activities led by Wen Tianxiang. After the defeat of the yuan resistance, the yuan army went south to crusade, and the Hakkas fled all the way to Hainan island.

The late Ming and early Qing dynasties were the fifth large-scale southward migration of Hakka. As the population of Hakkas living in Fujian, Guangdong and Jiangxi increased sharply, and Manchu invaded the Central Plains, Hakkas migrated to Sichuan, Hunan, Guangxi, Taiwan Province and the central and western regions of Guangdong.

Taiping Heavenly Kingdom is the sixth large-scale southward migration of Hakka.