Four Properties and five Flavors of Drugs is interpreted by adaptation of human body to the environmental theory(天人相應). The Structural model of the body is compared with sky, earth, sun and moon (天, 地, 日, 月). The natural changes of the four seasons give rise to that of Four Properties and five Flavors of Drugs. On equal terms it is happened in our body. On this study we can draw an analogy between sky, earth, sun & moon (天, 地, 日, 月) and the body. The six bu(六腑) is related to the earth, the five ju(五主) to the sky, the five jang(五臟) to the sun, the meridians system (經絡) to the moon. When spring, the air is warm, the water element of the earth is ascending, and the earth gives birth to the sour flavor. Like this, the water element is absorbed by six bu and then is ascended to the meridian system. When summer, the air is hot and the water element of the earth is floated, the earth make the bitter flavor. In the same way, the six bu absorbed the hot air from the five ju and the water element is quickly absorbed by six bu and then the water element is ascended to the meridian system. When rainy season (長夏), the earth creates the sweet flavor The sweet flavor give warmer energy to the five jang and the six bu. When autumn, the earth change the sweet flavor into pungent. The earth gives warmer energy to the sky, because of cool weather According to same process, the pungent flavor give warmer energy to the five jang and the six bu, and the meridian system gets back the water element from the five ju. When winter, the air is cold and the water element of the earth is hidden. The sky and the earth are not interchangeable. At that time, the earth produce the salty flavor and the water element is keeping in the meridian system.