Traditional Chinese medicine has always attached importance to the health prevention idea of"prevention before disease",which means that before the occurrence of disease,through the maintenance of healthy qi,enhance physical fitness,improve the ability of the body to resist evil.Huangdi Neijing is one of the ancient Chinese medical classics.Based on the whole concept of the unity of heaven and man,it draws on the wisdom of the hundred schools of health in the pre-Qin period,and puts forward that the way of health should conform to the change of seasons and climate in nature.The theory holds that the human body should maintain a harmonious balance with the Yin and Yang of heaven and earth in order to achieve the harmony and unity of the internal and external environment of the human body.This paper analyzes the theory of four-hour health preservation in Huangdi Neijing,introduces the principle and content of four-hour health preservation,and summarizes the function of four-hour health preservation theory in health protection