Abstract: 28 compounds isolated from Danshen (Salvia miltiorrhiza Bunge and S. przewalskii Maxium) were identified by both HPTLC and mass spectrometric analysis. The mass spectra of tanshinones and related terpenoids have been examined and a number of characteristic features noted which might be helpful in the identification of these compounds. The Rf values of five groups of tanshinones and related compounds in six solvent systems were given. They can be used for identifying several epimeric compounds which are difficult to identify by mass spectra alone.