The Book of Changes said, "It is easy to accurately grasp heaven and earth, so we can understand the way of heaven and earth. Looking up at astronomy and looking down at geography is the reason why you know the secret. It turned out to be the end, so I know the saying of life and death. " This means that language can only conform to the natural laws of heaven and earth if it follows the way of the change of heaven and earth. Only by looking up at astronomy and overlooking geography can we understand the mystery of natural change. From the above, we can see the close relationship between ancient geomantic omen and astronomical geography. Ancient geography books include Shangshu and Shan Hai Jing.