Since the 1970s, China has carried out a systematic and planned study on the essence of meridians and collaterals. So far, there are countless studies and hypotheses on the essence of meridians, but the academic circles have not yet reached a unified understanding. With reference to the research results of meridian essence in China in the past 50 years, the author summarizes the hypothesis of meridian essence from the point of view of ancient literature research, modern medical research and other hypotheses. It also analyzes the reasons for the phenomenon that there is no breakthrough opinion on the essence of meridians and collaterals so far, and puts forward some suggestions. The author believes that the essence of meridians and collaterals should be a three-dimensional structure with the integration of multi-systems and multi-functions, which is not only a real material structure, but also a functional structure, and the essence of meridians is also closely related to the physiological and pathological state of the human body. The purpose of this paper is to provide information reference and method enlightenment for the current research on the essence of meridians and collaterals.