TCM originated in the Spring and Autumn Period and the Warring States period, and its theoretical system was formed in the period from the Warring States to Qin and Han's dynasties and developed in the Western and Eastern Jin dynasties and the Sui and Tang dynasties, the Song, Jin and Yuan Dynasties, the Ming and Qing Dynasties, as well as the modern and contemporary times. The development of the theoretical system of TCM at each stage has its characteristics.
The theoretical system of TCM was formed in the period from the Warring States to Qin and Han dynasties, Huangdi's Canon of Medicine（Huan DiNei Jing）（referred to as canon of Medicine）, Classic of Difficult Issues（Nan Jing）, Treatise on Cold Damage and Miscellaneous（Shang HanZa Bing Lun）and Shennong's Classic material Medica（Shen Nong Ben CaoJing）marked its formation. These Chinese medical works laid a solid foundation for the formation of the theoretical system of TCM from the aspects of the basic theories, clinical syndrome differentiation, creating principles and methods and of TCM respectively.
