A large number of 13 C NMR spectra datas of oleanane saponins are studied and analysed in this paper. The characteristics of 13 C NMR spectra and the regularity of chemical shifts in the backbone of oleanane are obtained. The factors affecting the chemical shifts of oleanane saponins are discussed .The knowledge database for computer aided 13 C NMR spectra elucidation of oleanane saponins is established and something about the real...