Objective To develop a sensitive, simple, and accurate method for the determination of shionone in rat plasma after ig administration of Asteris Radix petroleum ether extract (RAPE). Methods The separation was achieved by HPLC on a RP18 column (150 mm × 3.9 mm, 5μm) with a mobile phase composed of acetotitrile-0.05% phosphoric acid water (98: 2) at a flow rate of 1.0 mL/min. UV Detector was set at 200 nm and friedelin was chosen as an internal standard. Results The linear range of the standard curves was (0.3443-22.0) μg/mL with the correlation coefficient of 0.9968. The intra- and inter-day precisions were all below 10% and the relative error was -3.5%-1.1%.Conclusion The developed method can be successfully applied to the pharmacokinetic study. After ig administration of RAPE, T1/2(ka) is (33.09 ± 7.32) min and T1/2(ke) is (84.95 ± 22.34) min.