According to legend, Su Wu was the attendant of an emperor in the Western Han Dynasty. He is honest, brave and knowledgeable. In order to make peace with the Huns, the Han Dynasty sent Su Wu 100 people to give them generous gifts. Before he left, Emperor Wu of the Han Dynasty summoned Su Wu and personally handed him a seven or eight-foot-long wooden stick. A string of wool balls hung on the top of the wooden stick, which indicated the identity of the messenger and proved it. When the Huns met Khan, the leader, Khan not only disagreed, but sent Su Wu to the North Sea (now Lake Baikal in Siberia, Russia) to graze. Also said that when your ram gave birth to a lamb, he would come back. Beihai is barren and snowy all year round. While grazing with a scepter, Su Wu thought of going south again one day and returning to his motherland. After several years of trekking, he came to Yanchi County. He was as happy as at home when he learned that this place was under the jurisdiction of Dahan. Here, he grazes, cultivates and recuperates, and gives the sheep in Mobei to local farmers to raise. Since then, Yanchi Tan sheep have gradually multiplied, and today's Tan sheep have emerged.

It is also said that Emperor Kangxi visited Xian in Xixia, pretending to be a scholar, and passed a mountain in the south of Huamachi (now Yanchi County) 100. The tired man was tired and hungry. Suddenly he saw plumes of smoke at the foot of the mountain. It should be a village. He went straight to the village. It turned out that the villagers were building houses and putting banquets on the beams. When the villagers heard that the scholars were coming, they gave them a warm reception. After steaming, frying, stewing, stewing and roasting, the mutton in Yanchitan is bright in color and delicious, which makes readers' appetite open, eat with relish and praise again and again. Why is the mutton here so delicious and fragrant? What good mutton! After half a year, the villagers knew that the scholar who ate mutton turned out to be Emperor Kangxi, and from then on, he had the reputation of eating good mutton and coming to Yanchi.