Abstract: The chemical constituents of essential oil of Nanguoli pear with ultrasonic extracting was analyzed with GC-MS method. The relative component percentage of each component was determined by area normalization method. The result showedthe yield of essential oil of Nanguoli pear with ultrasonic extracting was better than CK and increased when it prolong the time of ultrasonic. The sort of the chemical component of essential oil of Nanguoli pear with ultrasonic extracting was more than CK. The same of the main component were Butylated hydroxytoluene, Alpha-farnesene.

Key words: Nanguoli pear, ultrasonic extracting, essential oil, GC/MS