Objective: To establish characteristic fingerprint of volatile oils from Pilea aquarum by gas chromatography-mass spectrometry to determine the antimicrobial activities of volatile oils. Method: Chemical components of volatile oil from ten batches of P.aquarum were analyzed by GC-MS method

the common model and similarity of the TIC profiles were analyzed by “Computer Aided Similarity Evaluation System”

and the components of common characteristic peaks in chromatograms were identified. Antimicrobial activities of volatile oils were tested by filtering paper method. Result: Fingerprint of volatile oils from P.aquarum were established

sixteen characteristic peaks in GC-MS specific chromatogram of volatile oils from P.aquarum were identified and defined. The results also showed that the volatile oils of P.aquarum showed a cetain effect against Staphylococcus aureus

Escherichia coli and Bacillus subtilis. Conclusion: With a good reproducibility

the established characteristic fingerprints of volatile oil from P.aquarum can be used for quality control and provide important basis for application of volatile oils from P.aquarum.