Abstract: The essential oil was extracted from the different processed products of Angelica sinensis, the chemical composition and its changing regularity of essential oil was analyzed by GC-MS technique. Under the same extraction and measurement conditions, there was the remarkable difference of the components of essential oil in A. sinensis and its different processed products. Particularly there was a significant difference in the amount of chemical compounds such as (E)-ligustilide, (Z)-ligustilide and (Z)-butylidenephthalide. It suggested that the different processing methods could significantly affect the essential oil in the different processed products of A. sinensis, and there was certain physical basis to process A. sinensis according to its different clinical goal.

Key words: Angelica sinensis (Oliv.) Diels, different processed products, essential oil, steam distillation, Gas Chromatograph Mass Spectrometer (GC/MS)