Abstract: To analyze the constituents in supercritical fluid CO₂ extraction (SFE-CO₂) of Radix caulophylli, the Radix caulophylli was extracted with SFE-CO₂，and analyzed by gas chromatography-mass spectrometry (GC-MS). The GC-MS analysis with a DB-5MS capillary column (30 mm×0.32 mm ID, 0.25 μm film thickness) was used. The inlet temperature was maintained at 280 ℃. The column oven was held at 80 ℃ for 2 min, then programmed from 80 to 280 ℃ at 5 ℃·min^-1 and, finally, held for 4 min. Helium at a constant flow rate of 2.0 mL·min^-1 was used as the carrier gas. The mass spectrometry conditions were as follows: ionization energy, 70 eV; ion source temperature, 200 ℃. The mass selective detector was operated in the TIC mode (m/z was from 40-500). For the first time 49 peaks were separated and identified, the compounds were quantitatively determined by normalization method, and the identified compounds represent 97.44% of total GC peak areas. Viz, n-hexadecanoic acid (31.4%), (E,E)-9,12-octadecadienoic acid (26.54%), (Z)-7-tetradecenal (9.4%), hexadecenoic acid (3.23%), 10-undecenal (3.22%), octadecanoic acid (2.25%), and caulophylline (1.76%) etc. The results will provide important foundation for understanding the constituents and further exploitation of Radix caulophylli.