I -Ching: The Book of Changes , one of the most ancient and mysterious books in China, is so profound that it puzzles people of numerous generations . Its core thought lies in the binary complementarity of yin and yang to present diversities of the world. A set of organized signifier system yields changes of all creatures on the earth, which exactly reflects the philosophy of life and cosmos in ancient China. This book consists of two parts: The Upper contains 30 diagrams and The Lower 34 diagrams. The total of 64 diagrams demonstrates 384 complicated situations derived from interweaving changes in yaos. I-Ching research is basically bipartite: one focuses on ideas and the other figures and images. The former emphasizes the meaning of a diagram and develops consequent value of life philosophy, while the latter centers on what a diagram symbolizes, and explores relevant science. If science ever appeared in ancient China, then I-Ching can be the origin. The truth is: the development of mathematics in ancient China is not inferior to those in other civilizations. This paper intends to explore some mathematical issues such as the sequence of the innate 8 diagrams and the 64 diagrams, the quadrate and coordinate of I-Ching hexagrams as well as the rewritten images. Many mathematical thinkings are found amazing. Though I-Ching is like a treasure mountain of idea resources, this paper touches upon science and life cultivation alone.