The dialectical theory of yin-yang harmony in TCM health preservation theory originally refers to the backward direction of sunlight, the sun is positive and the back day is yin. Later, it gradually developed into a pair of important categories in China's ancient philosophy. It is an abstract summary of the two opposing sides of some interrelated things and phenomena in nature and two opposing factors in the same thing by the ancients. In the Book of Changes, which appeared from the end of the Warring States to the beginning of the Western Han Dynasty, the theory of Yin and Yang was comprehensively and systematically developed in the field of philosophy for the first time. Yi Zhuan contains rich dialectical thoughts. While fully affirming the eternal movement of the world, Yi Zhuan also focuses on the reasons for the changes of things' movements, and holds that all movements originate from the interaction of two opposing forces of Yin and Yang. The copula of Yi Zhuan says: "Combine rigidity with softness, change"; "The sun and the moon push each other, and life is bright"; "Cold and summer push each other, and the age becomes embarrassing." That is to say, no matter the cycle of spring, summer, autumn and winter, or the alternation of day and night, it is invariably produced by the interaction of yin (softness, moon and cold) and yang (rigidity, yang and summer). As the saying goes, "heaven and earth are alcoholized, everything is alcoholized, men and women are refined, and everything is transformed." It can be seen that everything in the world grows and changes in the interaction of yin and yang; If yin and yang are destroyed, the movement and change of things will cease to exist. On this basis, the author of Yi Zhuan clearly put forward "the way of saying one yin and one yang", and thought that the unity of opposites between yin and yang was the universal law of world movement and change. Philosophers and natural scientists in later generations mostly follow the train of thought of Yi Zhuan, and take the theory of Yin and Yang as their cosmology and methodology. Zhang Jiebin, a famous physician and health care practitioner in the Ming Dynasty, pointed out in Yin-Yang Classic: "Tao is also the principle of Yin and Yang. Yin and Yang, two thirds. Tai Chi moves to produce yang, while quietness produces yin; Born in motion, the earth was born in silence. Therefore, Yin and Yang are the way of heaven and earth. " "The way of heaven and earth, create everything with Yin and Yang; The principle of characters is that yin and yang are long. " Because of this, the law of yin and yang naturally became the basic program for the ancients to grasp and analyze the material structure, physiological function, pathological changes, dialectical treatment and health preservation and disease prevention of the human body. In fact, China's traditional health-preserving theory explains the phenomenon of life activities under the direct guidance of Yin-Yang theory, and constructs the theory and practice method of prolonging life. First of all, China's traditional health preserving theory holds that Yin and Yang are the fundamental attributes of human life activities. Su Wen's Angry Days said: "The foundation of life lies in Yin and Yang." The so-called "yin-yang origin" means that human life activities can be essentially attributed to the contradictory movement between Yin essence and Yang Qi. On the other hand, it means that the human body is an organic whole, and all its organizational structures can be divided into yin and yang, which are interrelated and opposed to each other. Secondly, the motherland's health theory holds that the balance of yin and yang is the basic symbol of human health. Huangdi Neijing puts forward the corresponding sign of human health: "Both yin and yang fill their shapes, and if they wait nine times, they are called average people." He also said: "Those who are flat are not sick, and those who are not sick are open-minded and treat others at all times. Up and down correspond to each other, but the meridians are also fixed, and the pulse of the six meridians does not move. Up and down correspond to each other, but the meridians are also fixed, and the pulse of the six meridians does not move. At the end of the day, the cold and warm are also in harmony, and the flesh and blood must be commensurate before they are called flat. " Since the balance of yin and yang indicates health, the destruction of balance naturally means the occurrence of diseases. Zhang Jingyue's "Jing Lei" in the Ming Dynasty holds that "human diseases, whether external or internal, cold or hot, or feeling five movements and six qi, or hurting viscera and meridians, are nothing more than yin and yang". Third, the theory of health preservation in the motherland takes the coordination of yin and yang as the most basic guiding principle. Su Wen Nu Tian said: "Harmony is sacred if Yin and Yang are not harmonious." The so-called "holiness" is essentially to take the coordination of yin and yang as the highest standard of health and longevity. It is under the guidance of the above principles that the health care practice of the motherland has gradually formed a set of specific methods to coordinate yin and yang. Now, here are some examples: the balance of yin and yang and the spirit of recuperation. This is what Huangdi Neijing said: "Yin and Pingyang are the secret, and God is the rule." ("Su Wen, Angry to Heaven". Five flavors harmonize and balance yin and yang. In the view of ancient health experts, all kinds of foods, like traditional Chinese medicine, have four different properties: cold, hot and cool, with five flavors: sour, bitter, sweet, pungent and salty. If the gender and taste of food are properly matched, it will help to maintain the balance of yin and yang and be beneficial to health; On the other hand, if the combination of sex and taste is not appropriate, it will break the balance of the body and damage health. Comply with nature and protect yin and yang. Huangdi Neijing mentioned: "The four seasons of Yin and Yang are the end of all things and the foundation of life and death. If you violate it, it will be disastrous. If you go against it, you can't afford it ... if you go against it, you will die. " This proves that the inversion of yin and yang will have a direct impact on the strength and life span of the human body. What is particularly valuable is that the balance understood by China's health preserving theory is not absolute static, but a special form of exercise full of contradictions. "Su Wen Liu Weizhi" put forward the viewpoint of "up and down, down and out, nothing", which means that the balance of everything in the world, including healthy "ordinary people", is in a relatively static state during the exercise.