Purpose: Yin-Yan(陰陽) is often seen with the mean of ascending and descending force in the Sasang Constitutional Medicine. In the PI(脾) and Shen(腎), oppositive interacting forces existe and causes the change that ascending and descending of Yin-Yan(陰陽). The purpose of this study is understand the mean of Pi-Yan(脾陽), Pi-Yin(脾陰), Shen-Yan(腎陽), Shen-Yin(腎陰) and their inter action in the pathology of Soyangin(少陽人) and Soumin(少陰人). Method: It was depended on the sentence that recorded in the Dongyi-Soose-Bowon(東醫壽世保元) Result: The following results have been obtained 1. The origen of Soumin's outer disease is ascending obstruction of Shen-Yan(腎陽), caused by deficiency of Pi-Yan(脾陽) 2. The origen of Soumin's interior disease is being cold of Shen-Yin(腎陰), caused by deficiency of Pi-Yin(脾陰) 3. The origen of Soyangin's outer disease is descending obstruction of Pi-Yin(脾陰), caused by deficiency of Shen-Yin(腎陰) 4. The origen of Soyangin's interior disease is being heat of Pi-Yan(脾陽), caused by deficiency of Shen-Yan(腎陽)