Judging from the historical development of China, the Silk Road opened in the Han Dynasty was sometimes interrupted by political opposition, ethnic conflicts and even wars. The development of civilization, the expansion of power, the activity of commercial nationalities, and the dependence between grassland nomads and those who have settled in agriculture have made the cultural exchanges between the East and the West never stop for more than 2,000 years. ?

At the end of the Eastern Han Dynasty, there were frequent wars and disorder in the Central Plains. Dunhuang, as the throat of communication between China and the West, can't even be a satrap for more than 20 years. Zhang Xiong's local strongmen annexed the land, which made the villain have no place to stand, and the western businessmen who came to do business were also defrauded. During 227-233, Cang Ci became the magistrate of Dunhuang, which effectively suppressed the merger and extortion of powerful people, provided various conveniences for businessmen from the western regions to buy and sell in the mainland, and made Dunhuang an international city for exchanges and trade between Han people and people of all ethnic groups in the western regions.

1907, the British archaeologist Stan found a group of letters written in the script of the Central Asian Sogdians under the beacon tower of the Great Wall in northwest Dunhuang. These letters were written by Sogdian merchants in Liangzhou (Wuwei) to the nobles in their hometown of Samarkand (present-day Uzbekistan), and were buried at the foot of the Great Wall in Dunhuang for some reason.

As mentioned in the letter, these Sogdian commercial groups based in Liangzhou operate long-distance sales of China silk and other commodities from Luoyang in the east to Dunhuang in the west. This group of letters was written at the end of the Western Jin Dynasty (around 3 12), which truly reflected the commodity trading activities on the Silk Road at that time.