Abstract: The dying out of Shang Dynasty is a catastrophe in ancient Chinese history. Scholars in successive dynasties have paid close attention to the causes of the disaster and formed various opinions. A major historical event usually results from multiple reasons. According to the comprehensive analysis of literature materials, the loss of Wei Yi in Yan should be one of the vital causes that were ignored in the past. Yan refers to Yan Li, a kind of special rite, and Wei Yi is the religious and political norm of Shang Dynasty, which combines sanctity and legitimacy. The loss of Wei Yi in Yan uproots the foundation of Shang Dynasty, leading to the crisis of internal strife, and finally to the dying out. It has a lot to do with King Zhou's supreme conceit. LI Si once summarized that the King overlooked minor mistakes and pursued pleasure all day long, bringing about the final destruction, which requires our attention.

Key words: the dying out of Shang Dynasty, Yan Li, Wei Yi, pay attention to political details