The chemical constituents of the essential oil of Hunan wild Artemisia annua L. in Xuefeng mountain region have been studied by means of the GC-MS. The essential oil was extracted from Artemisia annua L. by steam distillation. The chemical constituents were separated and identified by GC-MS, and the relative contents of them in the oil were determined with area normalization method. Forty-five components were separated and identified which accounted for 90% of total essential oil. These components identified from the essential oil indicate that Hunan wild Artemisia annua L. in Xuefeng mountain region is a good medical plant, and worth to exploiting.