OBJECTIVE To opti mize the supercritical CO 2 extraction technology of volatile oil from Blumea balsamifera ，and compare the components of the volatile oil from B. balsamifera obtained by supercritical CO 2 extraction and steam distillation. METHODS The volatile oil of B. balsamifera was extracted by supercritical CO 2 extraction. Using extraction rate of volatile oil as index，extraction temperature ，extraction pressure and extraction time as factors ，based on single-factor experiment ，orthogonal experiment was used to optimize the supercritical CO 2 extraction technology. Gas chromatography-mass spectrometry was used to identify the components of volatile oil from B. balsamifera . Peak area normalization was used to calculate the relative contents of each component. Taking the volatile oil obtained by steam distillation as a reference ，the extraction rates ，components and contents of volatile oil by the two methods were compared. RESULTS The optimal supercritical CO 2 extraction technology of volatile oil from B. balsamifera included extraction pressure of 30 MPa，extraction temperature of 50 ℃ and extracting for 50 min. After 3 times of validation tests ，average extraction rate of volatile oil was 4.64％（RSD＝0.54％，n＝3）. Thirty-nine components such as tritriacontane，stigmasterol，squalene were identified in the volatile oil of B. balsamifera obtained by supercritical CO 2 extraction； and 51 components such as triacontane ，ledol，humulene epoxide Ⅰ were identified by steam distillation. The extraction rate of volatile oil from B. balsamifera obtained by 2 methods were 4.64％ and 0.99％. A total of 26 common components were obtained ， such as xanthoxylin ，L-borneol，β-caryophyllene. Except for xanthoxyline （34.829％ by supercritical CO 2 extraction，30.676％ by steam distillation method ）and phytol （2.401％ by supercritical CO 2 extraction，1.273％ by steam distillation ），the relative contents of the components of volatile oil obtained by supercritical CO 2 extraction were lower than those of steam distillation. CONCLUSIONS The optimal supercritical CO 2 extraction technology is stable and feasible ；the components and contents of volatile oil obtained by two methods varies greatly ，and main compounds are aldehydes and ketones ，alkenes，alcohols and other components.