To analyze and compare the chemical components of the volatile oil in roots of Foeniculum vul-gare mill from ten different habitats. The volatile oil was extracted by steam distillation. The components of volatile oil were separated and analyzed by GC-MS. The relative content of each constituent was calculated by normalization. Result showed that twenty-six components in the volatile oil of roots of Foeniculum vul-gare mill from ten different habitats were identified. 13,7,11,10,14,11,14,11,10,10 components were identified from Xiaoerbage,Lawati,Tacheng,Bageqi,Shufu,Lasikui,Manglai,Yili,Moyu,Buzhake of Xin-jiang. Dill Apiol and 1,3-benzodioxole,4,7-dimethoxy-5-(2-propen-1-yl)-and 1,3-benzodioxole,4-me-thoxy-6-(2-propenyl)-are its common and main ingredients,which account for 90. 81% ~96. 18% and 0. 54% ~2. 76% and 0. 10% ~3. 33% of the total oils.