In the present study, Radix Codonopsis was extracted by supercritical CO2 extraction. As Ointment collecting rate and the yield of stigmasterol are index, Various reaction parameters were changed to attain the optimal conditions. The appropriate process conditions are size 40 - 60Mesh, 30 Mpa pressure, temperature 65 ℃, 120 min, entrainer Alcohol dynamic extraction (entrainer pump flow rate of 1 ml/min, the CO2 flow rate 2L /min.