Abstract: OBJECTIVE To establish an HPLC method for determining the contents of erianin and related constituent chrysotobibenzyl in Erianin emulsion injection. METHODS Agilent EclipseXDB-C₁₈ column(4.6 mm×250 mm, 5 μm) was used. The mobile phase consisted of methanol-acetonitrile-water(30∶30∶40), the flow rate was 1.0 mL·min^-1, and the detective wavelength was 232 nm. RESULTS Erianin and its related constituent chrysotobibenzyl were separated completely in Erianin emulsion injection. The calibration curves of both erianin and chrysotobibenzyl showed good linearity in the range of 5.562 5-89.0 μg·mL^-1 and 9.292-46.462 μg·mL-1, respectively(erianin: Y=13 504X+2 146.6, r=0.999 9; chrysotobibenzyl: Y=14.033 1X+2.388 6, r=0.999 9). The average recovery of erianin and chrysotobibenzyl was 100.8% and 99.82%, respectively. CONCLUSION The method is accurate, sensitive and with high specific, it can be applied for determining the contents of erianin as well as its related constituent chrysotobibenzyl in Erianin emulsion injection.