In the process of conquering the Xiongnu, Emperor Wu of the Han Dynasty learned from the mouth of the Xiongnu that there was originally a Dayue tribe living in the area of Dunhuang in present-day Gansu, and was forced to move west due to the attack of the Xiongnu. They hated the Huns to the core, and often wanted to come back to take revenge, but unfortunately their strength was weak and they could not resist the Huns. In order to unite the Dayue clan to fight against the Xiongnu, Emperor Wu of the Han Dynasty recruited people to envoy the Dayue clan, and Zhang Qian, a native of Hanzhong, was recruited as an envoy.
When Zhang Qian first went to the Western Regions, he was captured by the Huns on the way and imprisoned for more than 10 years, and then escaped by chance, and finally arrived at the Dayue clan. But at that time, the Da Yue clan had already taken root in Xindi, and did not want to fight with the Xiongnu again, Zhang Qian had to return, and was detained by the Xiongnu for more than a year on the way, and then fled back to Chang'an during the Xiongnu civil strife. Zhang Qian went to the Western Regions for the first time with more than 100 people, and when he returned, only two people, including him, remained.
Although Zhang Qian's first mission to the Western Regions was not successful, he learned about the topography, production and customs of the countries in the Western Regions along the way, which laid a good foundation for his second mission to the Western Regions. Zhang Qian was the first envoy of the Western Han Dynasty to open up the Western City, and his bravery and strong and unyielding qualities were recited by future generations.