Yi Li, Yi Xiang, Yi Shu and * * formed a complete Yi-ology system. "Zuo Zhuan Xi Gong fifteen years" said: "Turtle, like also; Oh, count. Things are born with elephants, and elephants are born with nourishment, and they are counted. " This is the beginning of clearly putting forward the concept of image number and explaining the relationship between image and number. Zuo Zhuan and Guoyu contain 22 examples, which preliminarily unify the meaning, image number and divination of Yi Gua. But at this time, the image mathematics has not yet been formed, and only an example of using the number of images is provided. The Book of Changes was formed in the middle and late Warring States period, which is the beginning of systematically studying image numbers in theory. According to the situation that the Book of Changes uses numbers instead of words, a set of principles of image number is put forward preliminarily. "On Cohesion" said: In the Yi Gua, "There are many complicated things to change. Through its changes, it has become an article of the world; A very small number will set the image of the world. " The so-called "image of the world" is to use intuitive and symbolic hexagrams to symbolize the nature and relationship of various things. Everything is mixed and changeable, and the relationship must be expressed by the number of images. Shuogua focuses on the images of eight diagrams such as heaven, earth, wind, thunder, water, fire, mountains and water, which provides a foundation for the further development of image mathematics.