•A new method was developed to separate and determine oxypeucedanin enantiomers.•Stereoselective differences were found in Angelica dahuricae Radix and rat plasma.•(+)-oxypeucedanin was present at a relative high level in Angelica dahuricae Radix.•(−)-oxypeucedanin showed higher plasma concentration in stereoselectivity. In this study, a new enantioseparation method was established for the quantitative analysis of the oxypeucedanin enantiomers by using cellulose tris(3,5-dichlorophenyl carbamate) stationary phase column Chiralpak IC. For this method, enantiomeric separation of oxypeucedanin was achieved with the mobile phase consisting of acetonitrile-water (60:40, v/v) at a flow rate of 0.5 mL/min by changing the type and proportion of mobile phase. And the quantitative determination of racemic oxypeucedanin in Angelica Dahuricae Radix (in vitro) and rat plasma (in vivo) were performed on above-mentioned condition by High PerformanceLiquid Chromatography combined with diode arrangement detector (HPLC-DAD) and mass spectrometry (HPLC-MS/MS). The precision, repeatability, stability, recovery were within the acceptance criteria. And the method was validated in the concentration range of 1-400 μg/mL for the two enantiomers in vitro and 0.2–600 ng/mL in vivo. After validation, the established method was successfully applied to the stereoselective analysis of racemic oxypeucedanin in Angelica dahurica from different regions and the stereoselective pharmacokinetic investigation in rat. Results showed that the (+)-oxypeucedanin was at a relative high level in Angelica dahuricae Radix and (−)-oxypeucedanin performed a higher plasma concentration, which demonstrated the difference of oxypeucedanin enantiomers both in vitro and in vivo.