Objective To establish a simple, fast, and highly sensitive analytical method for the determination of selenium in Codonopsis by hydride atomic fluorescence spectrometry. Methods Quantitative analysis of selenium in Codonopsis by atomic fluorescence spectrometry . Results The selenium content showed a good linear relationship in the range of 0~40μg/L, and correlation coefficient R² was 0.9999，detection limit of the method was 0.065 ng/mL;the sample recoveries was 113.33%，relative standard deviation (RSD) was 4.97%; the RSD of precision, accuracy and stability were 1.65%, 4.58% and 6.52%.The selenium content of 11 different varieties of Codonopsis was slightly different but all are below 0.1 mg/kg. Conclusion In the quality control and detection of selenium-enriched Codonopsis, the established method of selenium determination based on atomic fluorescence spectrophotometer was of good linearity, precision, and accuracy.