The theory of five circuits and six Qi belongs to the Shushu system ( schemes in ancient China), speculating the climate, phenology and their influence on life activity with the heavenly stems and earthly branches. It predicts diseases and calamities, and provides preventive measures. The knowledge source of this theory is mainly composed of three aspects: astronomy and the calendar, medicine and calamity, and Shushu. It has gone through many stages (initiation stage, embryonic stage, establishment stage,folk stage, official stage, etc. ) for its initiation, formation and development.