Abstract: This paper proves that ancient Shu in the Royal Record of Shu lasted 3500 years, of which dynasties from Cancong to Yufu 2000 years, with triple evidence from textural research, archaeology research and social historical information collection. Then it finds a 800 years vacancy between Yufu Dynasty and Duyu Dynasty. Judging from the information of their places, Cancong and Yufu were Di people with no tribal system and stable base, later migrated southward and then extinguished.