It is of necessity to explore the four notions of Ji (寄), Xiang (象), Didi (狄鞮) and Yi (译) in Book of Rites. No systematic and profound research has been conducted on the four notions. The present research on the four notions can help shed light on the connotation of "language of Yidi (夷狄)" used by Kong Yingda, the respective origins of Ji (寄) and Yi (译), the correspondence among Di (狄), Di (的) and Di (敌), and the far-fetchedness of "the popularity of Yi (译) on account of Han (汉)". All these serve to deepen the understanding of the four notions and offer a new approach to some related notions of modern translation studies.