Abstract:Essential oils were extracted from Michelia alba Dc. at perianth development stages by SPME and its chemical constituents were identified by GC-MS, their relative contents were determined by peak area normalization method. The results showed that chemical constituents at 5 perianth development stages were different，and 30, 29, 28, 30 and 27 constituents were identified, respectively. The main components were terpenoid, alkanes, ester, acid and alcohol compounds. Sixteen compounds were identified at more than 3 stages, in which 14 terpenoid compunds, 1 aromatic compound and 1 amine compound. There were 7 compositions only presented at IV stage, so it was considered to be the best stage to scent tea and extract essential oil. But if it couldn’t scent tea and extract essential oils in time or the transport distance was very far, the best harvesting stage is Ⅲ stage.