A fluorescence reagent quinoxaline-2,3-dicarboxaldehyde was firstly applied in the separation of amino acids by high performance liquid chromatography(HPLC).The reaction of primary amine amino acids with fluorescence reagent was studied in detail.The best conditions for the reaction:buffer:pH 9.5 100 mmol/L borate,a mole ratio of 2 mercapto ethanol,fluorescence reagent and amino acid:9∶3∶1,reaction time:5 min at room temperature.Under the optimal conditions,seventeen derivatives were detected with fluorescence detector after separation on a C18 column by gradient elution.The calibration curves were linear over the range of 0.01-1.00 mmol/L for all derivatives,with detection limits of 0.02-0.07 μg/L.This method was simple,rapid and sensitive,and was used for the measurement of the concentration of amino acid in ophiopogon of the Chinese traditional medicines with satisfactory results.