Yi nationality is a part of the frontier ethnic groups active in northwest China during the pre-Qin period. After moving south, it merged with local aborigines and gradually formed national identity. During the Qin and Han Dynasties, Yi ancestors were widely distributed in Yunnan-Guizhou Plateau and Hengduan Mountain Area.
According to the ancient documents of Yi language, after the Yi ancestors established a powerful slavery regime in northeast Yunnan, their six sons, divided into six branches, developed around and conquered western Guizhou, southern Sichuan and most parts of Yunnan.
In the 4th century, three political, economic and cultural centers were formed: Dianchi Lake, Qiongdu and Yelang. During the Western Han Dynasty, Emperor Wu of the Han Dynasty sent troops to conquer "Southwest Yi" and set up a county, and the Yi region was formally incorporated into the rule of the Central Plains dynasty. Around the 8th century A.D., there were six groups of Wuman tribes in the northern part of Ailao Mountain and Erhai Lake in Yunnan, which were called "Six Letters" in history, among which "Meng She Letters" appeared.
In 783 A.D., the founder unified the "Six Letters" and established the "Nanzhao State" with the Yi people as the main body, including the ancestors of the Bai and Naxi nationalities. At the same time, the "Luodian State" slavery regime also appeared in the Yi area of Guizhou. There are forces of Northern Lan, Middle Qu and Southern Jiang in Liangshan, all of which have formed regions. In 937 ad.
Duan Siping established Dali Kingdom with the support of Wuman 37 Department. In A.D. 1253, the Mongolian army attacked Yunnan, which led to the unification of the divided Yi region under the name of "Luoluo" and jointly fought against the Mongolian army. After the failure of resistance, the Yuan Dynasty implemented the chieftain system in the southwest, and now it is in Yuexi, Xichang, Pingshan, Dafang, Zhaotong, Weining and Chuxiong.
Red River and other places are easy to be divided into toast. During the Yuan and Ming Dynasties, a large number of Han immigrants moved to Yunnan-Guizhou Plateau and Hengduan Mountain Area. In addition to military camps, military camps and private areas have been promoted on a large scale. By the Ming Dynasty, more than 400,000 Han people had rented agricultural land from Yi Tusi, and the areas where the Yi people originally lived together also developed into mixed areas of Yi and Han people. With the increasing proportion of Han nationality, Yi people can only retreat to the mountains.