The theory of five circuits (yun) and six climatic factors (qi), an indispensable part of Traditional Chinese Medicine,studies the cycle of climatic changes and its influence on life activities. According to the theory of Huangdis Internal classic,The influence of ganzhi (heavenly stems and earthly branches) yunqi on life activity is not limited to the development of diseases or syndromes related to changes of yunqi within corresponding year; this impact also extends to inherent physical constitution determined by the yunqi of pregnancy year. This physical characteristic is also associated with its susceptibility to diseases. Yunqi theory originates from the theory of qi transformation in Huangdis Internal classic,which is the extension of qi-monism theory in ancient philosophy.