The objective is to develop a method for the determination of paeoniflorin in Weidening tablet.An HPLC method was developed, mobile phase:methanol-0.05 mol/L potassium dihydrogen phosphate-acetic acid-iso-Pr alc. (50:200:3:4), wavelength at 234 nm.Linearity was found in the range of 1.018-9.183 μg, and the average recovery was 100.7%, RSD = 2.76% (n = 5).This method is reliable, recurrent well and suitable for the determination of paeoniflorin.