To discuss the hypothesis of the sensitization state of acupoints based on the original definition and the localization method of acupoint from Internal Classic as well as the clinical evidence of heat-sensitive moxibustion. Acupoints are different in the states, named resting and sensitization. The acupoints of sensitization state are the reactive sites of disease on the body surface, also the best sites for acupuncture and moxibustion treatment. The acupoints are the specific sensitive sites on the body surface relevant with diseases with the best therapeutic effects. Hence, the acupoints of sensitization state are of dynamic variability. In clinical application, only the two-step location method, preliminary and accurate localizations (sensitive probing localization) from Internal Classic can localize the acupoints precisely, rather than one-step location method such as proportional measurement or body surface landmark localization. The nature and property of acupoints are different based on the functional state, not just on the fixed locations.