Abstract: Flowers and fruits of Alpinia officinarum were extracted by hydrodistillation method to get the essential oil, whose chemical constituents were analyzed by GC-MS, and whose antimicrobial activities were assayed by filter disks. The results showed that contents of essential oil in fresh flowers and fruits of A. officinarum were 0.003% and 0.209%, respectively. The main constituents in its flowers were caryophyllene oxide (40.63%) and 茁-caryophyllene (11.14%), while those in its fruits were 琢-cadinol (41.20%) and 子-cadinol (22.88%). The essential oils from flowers and fruits of A. officinarum both had inhibitory effect on the growth of Staphyloccocus aureus and methicillin-resistant S. aureus (MASR).