Objective To compare the effects of SFE - CO2 extraction and steam- distillation extraction for the extraction of volatile constituents from Huoxiang Zhengqi prescription. Methods The recovery rate of the volatile constituents and GC- MS method were used to compare the two different extraction methods. Result The recovery rate of volatile constituents was 0.45 % when extracted by steam distillation for 5 hours and 2.40 % by SFE - CO2 extraction for 3 hours. A large amount of peaks were detected in the SFE - CO2 extraction, while few compounds could be detected in the steam distillation extract 15 minutes later. Conclusion SFE - CO2 extraction method is a better method for the extraction of volatile constituents from Huoxiang Zhengqi prescription,with higher recovery rate, obtaining more ingredients and costing less time compared with those by steam distillation extract method.