Abstract: The essential oil of Hongxiangsu pear was extracted through the ultrasound method, and was investigated by gas chromatography-mass spectrometry (GC-MS) technique. The highest yield of the essential oils of Hongxiangsu pear extracted by the ultrasound method in 30 min was 0.366%.The identification of the volatile compounds was conducted through the commercial NIST and Wiley mass spectral search program, accompanied by the confirmation with comparing the retention indices with standard values of authentic samples. A total of 24 components were identified from the essential oils including vinyls, esters, alcohols, aldehydes and ketones. The predominant constituents of the essential oils in Hongxiangsu pear were Nonanal and buty- lated hydroxytoluene.

Key words: Hongxiangsu pear, ultrasound, GC/MS, volatile oil