The interactive relations between Daoism and Traditional Chinese Medicine can be traced back to the Han dynasty, where Daoist organizations were initially found. There is an essential sequence that lies behind the studies on the relationship between the two: Traditional Chinese Medicine is always comprehended as professional knowledge developed before Daoism, or its origin, the Laozi. As a result, Daoism had become a religion that inherited this well established medical knowledge to construct its religious ideas and believes. In this presentation, we will raise challenges to this sequence through a comprehensive and comparative study on the Theory of Heart in Wenzi and Huangdi Neijing. The Theory of Heart is vital in Traditional Chinese Medicine. By understanding the enhancement of this theory, we will argue that the theoretical system of Traditional Chinese Medicine could not have developed properly earlier than Laozi and Wenzi. The Theory of Heart was a product advanced in the Jixia Academy, with Laozi and Wenzi as the central source for discussion resulting in the theory to be established. Besides, theories, practices, and clinical applications of Daoist cultivation also made significant contributions to the development of the theory. We hope this presentation will fill in some of the blanks regarding the interactive relations between Daoism and Traditional Chinese Medicine and give us a better picture of how Daoism impacted the history of Traditional Chinese Medicine.