Objective : Through the comparison of the Eumyang(陰陽) theory between Hwangjenaegyeong(黃帝內經) and Juyeok(周易) Gyesajeon(繫辭傳) written by Gongja(孔子), the philosophical background of Hwangjenaegyeong(黃帝內經) and the position of Eumyang theory in the ancient academic society can be clearly understood. Method : The similarities and differences of the Eumyang theory in Hwangjenaegyeong(黃帝內經) and Juyeok(周易) Gyesajeon(繫辭傳) are categorized and analyzed comparing both texts. Results & Conclusion : Hwangjenaegyeong(黃帝內經) and Juyeok(周易) all recognized Eumyang movement as the most important and basic principle of the change of the universe. In the relationship between Eum(陰) and Yang(陽), the key of harmonization of them is to keep and practice the virtue of each others. The plentiful expression of Juyeok(周易) Gyesajeon(繫辭傳) about the relationship of Eumyang is helpful to understand and apply the concepts of Eumyang to daily life. The other hand, Hwangjenaegyeong(黃帝內經) as medical text, concentrates upon the explanation about the movement and circulation of Gi(氣) between Eum and Yang.