The therapeutic effects of acupuncture are well known. Based on previous and existing experimental results, we combine the basic theory of acupunture and meridian with that of neuroendocrine immune system and propose a new tentative theory of human meridian. We hypothesize that the human meridian system consists of neuroendocrine immune networks with numerous sensitive nodes and their functional connections. The complex meridian networks are then not only spreading over the whole human body but also taking effects on body through those sensitive nodes and their functional connections.