The analysis of essential oil in seeds ofDeseurainia sophia provided an experimental basis for further research on essential oil activity test at the first time. Essential oil was extracted by steam distillation method. Analysis and identification were made by gas chromatography-mass spectrometry (GC-MS) technology in combination with retention indices. A total of 33 components in seeds ofD. sophia were detected by GC-MS and 28 compounds were identified by MS in combination with Kovats retention index. The compounds with high contents were as follows: 3-methylene-nonane (68.14%), 1,3-diazine (29.32%), 2-n-butylacrolein (0.58%), methyl nipecotate (0.43%), 4-oxo-butanenitrile (0.31%), 8-chloro-neoisol-ongifolene (0.25%) and so on. It was concluded that 28 volatile components were identified by GC-MS combined with retention indices. The total detected components were 99.91%. This method was able to improve the accuracy of qualitative detection results.