Abstract: In order to make clear the natural volatile composition of frankincense and the differences between fresh frankincense and cooked frankincense, to provide a scientific basis on improving techniques and evaluating qualities of frankincense volatile oil, and to offer a new method to analyse volatile composition from solid for reference, the volatile components of natural fresh and cooked frankincense were extracted and determined directly by thermal desorption and gas chromatography-mass spectrometry(GC/MS). More than 40 components are separated and 20 components are identified by comparing their mass spectra with those contained in the NIST mass spectral database and Mass Works^TM software.The results show that the main components includ terpenes, alcohol and esters et al, n-octyl acetate is the most important volatile components to frankincense. The normalized peak areas exceed 50% both in fresh frankincense and cooked frankincense,followed by 1-octanol, linalool and bornyl acetate, the normalized peak areas in fresh frankincense are 19.44%,2.27% and 2.64%, in cooked frankincense are 9.12%, 2.61% and 1.33%, respectively.