Objective: To determine the optimal processing method for Fructus Forsythiae. Method: HPLC was applied on the determination with Alltima C18 column (4.6 mm×250 mm

5 μm) and methanol - water as mobile phase by a gradient elution program at a flow rate of 0.8 mL ·min-1. The detection wavelength was at 280 nm and column temperature was at room temperature. Result: The regression equation of Forsythiaside was Y =959 631.703 1 X +250 467.648 4

r =0.999 4

Linear range was 1.5-15 μg

The regression equation of phillyrin was Y =883 203.205 8 X -9 047.738 3

r =0.999 4

Linear range was 0.145-1.45 μg. The average recovery of Forsythiaside and Phillyrin was 97. 9% with RSD 2. 30% and 99. 2% with RSD 2. 27% (n= 6 ) respectively. Content of the Forsythiaside and Phillyrin was in the maximum yield with the processing methods of steaming for 20-30 min steaming. Conclusion: The method was accurate and repeatable

can be applied to the quality control of Fructus Forsythiae. The optimal processing method of Fructus Forsythiae was steaming for 20-30 min.