Abstract: OBJECTIVE To establish a method of HPLC for the determination of isomer in dapoxetine hydrochloride tablets. METHODS The column of DAICEL CHIRALPAK OZ-H (250 mm×4.6 mm, 5 μm) was used. Column temperature was 40℃, detection wavelength was 293 nm, flow rate was 1.0 mL·min^-1, and the mobile phase consisted of n-hexane-isopropanol-diethylamine(80:20:0.05). RESULTS The calibration curves of dapoxetine hydrochloride and isomer were linear over the range of 0.01-0.50 mg·mL^-1(r=0.999 9). The limit of quantification was 0.002 mg·mL^-1(equivalent to 0.02%). The minimum detection limit was 0.001 mg·mL^-1(equivalent to 0.01%). The limit of quantification of isomer was 0.001 mg·mL^-1(equivalent to 0.01%), and the minimum detection limit was 0.000 5 mg·mL^-1(equivalent to 0.005%) CONCLUSION The method is proved to be simple and accurate, which is suitable for the content determination of optical isomer in dapoxetine hydrochloride tablets.