Abstract: The HPLC chromatogram of gromwell extract consisted of about 20 peaks and the analysis lasted 75 min, The retention time of β,β-dimethylacryl shikonin is about 55 min. It is time-consuming to prepare the calibration curve, The present paper reports a flow cell calibration methed and its application in analyzing the gromwell extract. The results of this method are in good agreement with the absolute calibration method. The latter method is very time-consuming.