Charm physics at BESⅢ

Since the discovery of J/Ψ and the τ lepton in 70’s, the study of τ-charm physics became very active: several dedicated e+e- colliders were built and tremendous progress were obtained. In this paper, the main reasoning, the content and the characteristics of the τ-charm physics study are discussed, together with the scientific motivations and the latest results of the recently completed upgrade of the Beijing Electron-Positron Collider(BEPCⅡ) and the new Beijing Spectrometer(BESⅢ).