The theory of interrelation between acupoints and viscera (IBAV) is one of the most important parts in Traditional Chinese Medicine and the key concept in the theory of Zangfu and Jingluo (meridians). IBAV expresses the rule between body surface and inner organs which guides the diagnosis and treatment in acupuncture practice. Yellow Emperor said: "The twelve-channel is the passage of the flowing of the blood and energy in human body, it has close relation with the existence of the flowing of the blood and energy in human body, it has close relation with the existence of man, the forming of disease, the human health and the recovery of disease..." (Chapter 11 Jing Bie Yellow Empero’s Canon Internal Medicine) Early studies noted that IBAV is bi-directional by reflex reaction to the acupoints on body surface. Stimulation on the acupoints can simultaneously regulate visceral functions. Recent research showed that acupuncture stimulations induced neuronal nitric oxide expression in the brainstem. Nitric Oxide in the medulla medicates various physiological reflexes. In this Review, the evidence of the relationship between viscera and acupoints will be summarized and emphases on the study of interrelation between acupoints and viscera is not only for improving clinical effects, but also for clarifying the mechanisms of acupuncture-moxibustion. A main way to treat visceral illnesses is choosing acupoints based on differentiation of symptoms and signs.