Abstract:The volatile constituents from the leaves of different Eucalyptus species were analyzed by gas chromatography-mass spectrometry(GC-MS). They were extracted by steam distillation and identified by GC-MS method. In the identified components,Eucalyptol and p-menth-1-en-8-ol are common in the leaves of these five Eucalyptus species:Eucalyptus exserta,E.urophylla215;E.grandis,E.pellita,E.urophylla,E.robsta. Rhodinal and critronelly acetate are the main components in the leaves of E.citriodora. The results indicated that volatile constituents and their relative content in the leaves of different Eucalyptus species are different.