Abstract: The lignan constituents from Schisandra chinensis (Turcz.) Baill. fruits of different localities in China were investigated by electrospray ionization multiple-stage tandem mass spectrometry (ESI-MSⁿ) in the positive ion mode. The data of molar masses and detailed structural information were obtained. The major lignan constituents in the fruits drug were identified. Compared the number and concentration level of lignans in the three samples, their sameness and difference were found. The experimental results indicated that the ESI-MSⁿ method offer an effective way for the analysis of bioactive constituents in Traditional Chinese Medicine (TCM), which has the advantages of sensitivity, rapidly and convenience.