Objective To study the effect of Five-Yun Six-Qi endowments on the incidence of hypertension.Methods The Five-Yun Six-Qi endowments in 48

666 cases of essential hypertension were extracted by taking Beijing resident population as control. The birth times and Five-Yun Six-Qi endowments in populations susceptible and non-susceptible to hypertension were analyzed. The internal relation was discovered. Results The populations susceptible to hypertension（ 9 kinds in male and 11 in female） were mainly born in spring or summer. The populations non-susceptible to hypertension were mainly born in autumn or winter. The host Five-Yun Six-Qi endowments in populations susceptible to hypertension had more autumn and winter qi and less spring and summer qi. The host FiveYun Six-Qi endowments in populations non-susceptible to hypertension had average season yin and yang qi. The populations susceptible to hypertension often had two phases and the populations non-susceptible to hypertension often had one phase. The common characteristics in male and female populations susceptible to hypertension were endowments of restraining among the five phases at the same time. Year-qi endowment in most male patients were dominated by a coexistence of metal and wood

while female were dominated by a coexistence of water and fire. There were situations of coexistence of dominant water and fire

metal and wood

earth and wood

or excessive earth and metal followed with the avenged wood and fire both in males and females. On the other hand

the Year-Qi of most people not liable to hypertension was yin-yang balanced. Conclusion The Five-Yun Six-Qi endowments are related to the occurrence of essential hypertension. Essential hypertension belongs to Jueyin disease and yin syndrome. This study provides a new method for exploring the internal cause of disease from Five-Yun Six-Qi endowments.