Man's fundamental understanding of the universe is inseparable from man's understanding of himself. Because people are not isolated, people and heaven and earth, everything and nature are a unified whole. 1. Man is the product of the highest stage of natural change on earth. Although human beings evolved directly from advanced animals, the evolution law and material characteristics of the earth from inorganic substances to organic substances to organisms to lower animals to higher animals to humans are all deposited in human life. Every step forward in this long evolutionary chain is the result of the interaction between nature and it, so the human body is always a unified whole that is interrelated with everything in the world and plays a common role. 2. Human beings are exchanging materials, energy and information with nature all the time. At the same time, human beings can not only passively accept external information and changes, so as to maintain complete contact with the surrounding environment, but also actively respond to nature to meet the requirements of human life. All these make the relationship between human beings and nature closer, and with the development of human beings, the quality, breadth and depth of the overall characteristics of human beings and nature are constantly developing and changing. 3. People and everything in the world are rooted in a spirit. The holistic view of the unity of man and nature holds that all things originated from one spirit, so they maintain internal identity with each other. In view of the fact that people and everything evolved under the background of primitive qi, qi has become the medium of all things' connection and the basis of all things' interaction. In this regard, we will discuss it in detail in "Qi Theory". People ingest foreign substances for their own use. The whole life process of human beings is a process of constantly absorbing external substances for their own use, and it is also a process of interaction and continuous integration with the outside world.