Abstract: By exploring the discussions about the nine-needle in Neijing and making a summary of its number shapes and applications， we find that the nine-needle theory has the feature of concerning morphological structure which is the same as new acupuncture tools and therapies today and very different from "mind-balance" of filiform needle. However， we consider that the nine-needle theory which possesses the feature of "structure-needling" should but did not have enough influence on the development of acupuncture. So we call for paying more academic attention to "physics" during the development of modern acupuncture and making acupuncture more practical.