An HPLC method was described for the determination of Paeoniflorin in Paeonia Lactiflare Pall and its set prescription preparations, Paeoniflorin was separated on an ODS column with a mobile phase of methanol-tetrahydrofuran-water (17:3:80, v/v/v) and detected at 230 nm. The result was calculated by external standard method. The recovery of Paeoniflorin in Paeonia Lactiflare Pall is 96.2% with relative standard deviation of 0.76%.