Objective: To define the concept of meridian theory.
Methods: Characteristics of meridian theory were systematically analyzed by the comparison of differences of doctrine and theory concepts and according to practicality, abstraction and logicality of scientific theory.
Results: Meridians have various characteristics of scientific theory, so it should be a scientific theory.
Conclusion: Meridians are not a doctrine, but is a scientific theory. That the meridians are defined as scientific theory is of important practical significance for studies of meridian essence and standardization of acupuncture and moxibustion, and innovation of theoretical system of acupuncture and moxibustion.