OBJECTIVE：To investigate the composition-activity relationship of the antioxidant active component in essential oil of Lavandula angustifolia from Xinjiang. METHODS ：Antioxidant activity of essential oil of L. angustifolia was evaluated with 1，1-diphenyl-2-picrylhydrazyl（DPPH）free radicals scavenging method. GC-MS combined with retention index were adopted to qualitatively analyze the compounds. The relationship of chemical components with antioxidant activity of essential oil of L. angustifolia was analyzed by principal component analysis （PCA） and partial least squares analyses （PLS）. The variable importance in projection （VIP＞1）was used to screen the components which had great contribution to the elimination of DPPH free radical. RESULTS ：The IC 50 values of essential oil in 9 batches of L. angustifolia from 3 different varieties was 4.82-9.88 mg/mL，IC50 of France blue was 6.66-8.58 mg/mL，IC50 of H- 701 and Xinxun- 4 were 4.82-7.73 mg/mL and 9.55-9.88 mg/mL，respectively. A total of 40 chemical components were identified of essentil oil in 9 batches of L. angustifolia . Results of PCA analysis showed that accumulative variance contribution rate of former 2 main components was 81.8％；9 batches of samples were divided into 3 regions， and different varieties were classified into one category ；the characteristic variable components of the essential oil of French blue samples were lavandulyl acetate corresponding to peak 32 and trans- β-ocimene corresponding to peak 9；the characteristic variable components of the essential oil of H- 701 samples were linalool corresponding to peak 16，linalyl acetate corresponding to peak 30 and terpinen- 4-ol corresponding to peak 21；the characteristic variable components of the essential oil of Xinxun- 4 samples were eucalyptol corresponding to peak 8，camphor corresponding to peak 18 and 2-borneol corresponding to peak 20. The compound with the greatest antioxidant activity was linalool corresponding to peak 16 （VIP＝2.940 0），followed by terpenein- 4-ol corresponding to peak 21（VIP＝2.863 1），caryophyllene corresponding to peak 35（VIP＝2.570 8）and eucalyptol corresponding to peak 8（VIP＝2.115 8）. CONCLUSIONS ：The essential oil of L. angustifolia has certain antioxidant activity ，and H- 701 sample has higher antioxidant activity. Linalool corresponding to peak 16 is the most important component of essential oil of L. angustifolia in eliminating DPPH free radical.