OBJECTIVETo probe into the original meanings of manifestation and root cause, root and knot, Genliu infusion, Benshu, pathway of qi, four sea, Guan-He Shu and other classical channel theories.

METHODSBased on Huangdi Neijing (The Yellow Emperor's Internal Classic) and other classical literatures, combined with medical books in bamboo slip and the silk and opinions of annotation experts of successive dynasties, deeply analyze and study.

RESULTSClassical channel theories are involved in some theories of channel structures, with 3 original meanings: expounding the origin, the end and running of channels, expounding bi-directional running of channel-qi, and expounding the affinity relation of six channels, six qi, six zang-organs and six fu-organs.

CONCLUSIONClassical channel theories stress emphasize concentric running of channels, and concentric arrangement of channel acupoints, bi-directional running of channel-qi, and each affinity of six channels.