Objective: An HPLC method was established for the simultaneous determination of imperatorin and isoimperatorin in Radix Angelicae Dahuricae.Methods: The separation was performed on a Agilent ZORBAX SB-C18 column(4.6 mm×250 mm,5 μm) using methanol-water(70∶30).The UV detection was set at 254 nm;flow rate was 1.0 ml/min.Results: There was good linearity between the peak area and concentration at the ranges of 0.094 8-0.853 2 μg/ml(r=0.999 8),0.150 0-1.350 0 μg/ml(r=1.000 0) for imperatorin and isoimperatorin respectively.The average recoveries of imperatorin and isoimperatorin were 98.0%(RSD=1.0%) and 99.0%(RSD=0.5%).Conclusion: The method is rapid,simple and accurate for the content determination of imperatorin and isoimperatorin in Radix Angelicae Dahuricae.