Since Chen Tuan formed his theories, Tu-shu yixue in the Song Dynasty, different from traditional philosophical thinking, has been approached and interpreted in innovative ways, known for its richness in contents both in the fields of Xiangshu and Yili, and for its wider scope of interpretations. Liu Mu's and Shao Yong's theories of Tu-shu yixue had had great influence and become one of the important features in the development of Yi studies since Southern Song Dynasty. Zhu Yuansheng was a predominant figure in the field of Yi in the mid-late Southern Song. He composed 116 Yi-diagrams in his San Yi Bei Yi, with thoughts closely related to Liu Mu's and Shao Yong's views. Zhu systematically incorporated Lian shan yi, Gui cang yi and Zhou yi with Xiantian, Zhongtian, and Houtian. The rich and complex contents of Zhu's San Yi Bei Yi provide profound insights into the understanding of Yi. This article aims to explore the thoughts, diagrams, and contents in three Yi-related books, and the important meanings the books convey