Abstract: Supercritical fluid extraction(SFE) is a new separation technique.An useful apparatus based on the combination of SFE principle with the reflux technology and on the actual condition,was designed for the reflux and low pressure SFE of carbon dioxide and has resolved the critical experimental means.The reliability,low cost and application value of the apparatus has been proved excellently by extracting glycyrrhizic acid from licorice from licorice root.