The article aims at providing theoretical foundation for security of moxibustion through analyzing chemical compositions of Artemisia Argyi of different years from Qichun County, Hubei Province, and moxa wool refined in different proportions. Artemisia Argyi from Qichun on 2007, 2008 and 2009 were taken as raw materials, and processed into moxa wool with the proportions of raw material and product as 3 : 1, 5 : 1, 8 : 1 and 15 : 1, respectively. Essential oils of Artemisia Argyi and the refined moxa wool were extracted by steam distillation. Their chemical compositions were identified by gas chromatography-mass spectrometry (GC-MS) and calculated with semiquantitative method. The result showed that chemical compositions of Artemisia Argyi of different years and moxa wool refined in different proportions were almost the same, but their contents were with obvious difference. The relative content of volatile substances decreased with the age prolonged and a rise in the proportion of the refined moxa wool, while the involatile material increased. Therefore it can be concluded that the essential oil of Artemisia Argyi from Qichun and the refined moxa wool is basically safe. Involatile substances such as Juniper camphor, Caryophyllene oxide and Caryophyllene etc. are the main contents of high proportional moxa wool of old year. And these substances may be the effective components in moxibustion treatment.