Objective To make an attempt at some conditions on extracting heavy metals in chry-soidine by supercritical CO_2 extration.Methods Taking sodium diethyldithiocarbamate trihydrate(NaDDC?3H_2O) as chelating agent and ethanol as entrainer,the orthogonal test was designed and ICP-MS used to mensurate the contents of Cu,As,and Pb in chrysoidine under different conditions.According to the results,the factors including extracting pressure,temperature,chelating agent dosage,and time were studied.Results When the test sample was 10 g,the optimum condition was that extracting pressure: 25 MPa,the temperature : 60 ℃,chelating agent dosage: 2 g,extracting time: 3 h,and the ethanol dosage: 10 mL.After extracting reaction,the contents of heavy metal in chrysoidine reached United States FDA standard.Conclusion The contents of heavy metal in Chinese herb medicine are notably decreased,and this way provides a new thought and research technique to decrease the contents of heavy metal.