The “I Ching” is believed to has its roots in all Chinese classics and even in Chinese culture. It has been influencing greatly on Chinese classical culture. Traditional Chinese Medicine, as an essential component of Chinese culture, has also been under the influence of the “I Ching”, especially in the development of its theoretical foundation. Therefore, many of the ancient and modern physicians have explored the relationship between the “I Ching” and Traditional Chinese medicine. This article aims to explore the similarity of thoughts between the “I Ching” and Traditional Chinese Medicine. Literature selected includes the yin and yang theory, hexagram and line statements and Ten Wings of the “I Ching” as well as elaborate treaties of subsequent generations. Theoretical foundation, namely, the theory and thinking pattern of Chinese medicine, was taken from “Yellow Emperor Book of Internal Medicine”. The results show that the relationship between the Traditional Chinese Medicine and the “I Ching” share analogical thought, intuitive thought, experience thought, systemic thought and dialectical thought. This research will also contribute to the understanding of Traditional Chinese Medicine’s theoretical structure.