OBJECTIVE A RP-HPLC method was established for the determination of phillyrin in Shuanghuanglian tablets.METHOD The Nova-Pak C18 column (250 mmX 4.6 mm, 10 f*m) was used. The mobile phase was consisted of acetonitrile-water(25:75) with the flow rate at 1.0 mL- min～1 and the UV detection wavelength was at 277 nm, RESULTS The calibration curve was in good linearity over the range of 0.432~2.59 /ig.and the regression equation was V = 595.57 X + 1.619( r = 1.000 0). The average recovery was 97.50% (RSD = 1.41 % n = 5) ,RSD of reproduction was 1. 98% ( n = 5). CONCLUSION The method is simple,quick,sensitive,accurate,reproducible and can be used to control the quality of Shuanghuanglian tablets.