Abstract: The volatile constitutes of Cnidium monnieri were extracted by hydro-distillation and supercritical CO₂ extraction. 48 compounds are determined in these extracts，and are identified by capillary gas chromatography combined with mass spectrometric detection. 31 components are identified by hydro-distillation, while 21 components are identified by supercritical CO₂ extraction. 6 coumarins including osthole, imperatorin, isopimpinellin, bergapten, xanthotoxin and xanthotoxol are detected in Cnidium monnieri (L.) Cuss. The results show that supercritical CO₂ extraction for the volatiles from Cnidium monnieri (L.) Cuss. is more selective. The structure identification of osthole was discussed by mass spectrometry.