Abstract: Dan-Shen, the root of Salvia miitiorrhiza Bunge, is a well-known Chinese traditional drug used for treatment of various kinds of diseases including coronary disorders. For the exploration of the active principles, the chemical components of this drug were studied and ten crystalline compounds were isolated. According to chemical analysis and spectral data, eight crystalline compounds were identified as Baicalin, β-Sitosterol, Cryptotanshinone, Ursolic acid, Doursterol, Protocatechuic aldehyde, Isoferulic acid and Dihydrotanshinone I. Baicalin, Ursolic acid, Doursterol and Isoferulic acid were isolated for the first time from this plant. Besides, two unknown components were also obtained, one of which, with the structure of (Ⅷ), has been deduced from spectral data as well as by conversion into known component (dihydrotanshinone Ⅰ). It was named dihydroisotanshinone Ⅰ.