Acanthopanax senticosus called Siberian Ginseng has not only a medical benefit for tonic, lumbago, neuralgia and palsy, but also an active operation on metabolism. In this work, the A. senticosus was purchased from Korea Siberian Ginseng Association. The ethanol extract from the powder of the trunk of A. senticosus was partitioned with water and hexane. The resulting solution was purified on a preparative column (3.9x300 mm, 15 mum, Lichrospher 100RP-18). The mobile phase composition for isolating acanthoside-D from extract was water/acetonitrile/methanol, 80/14/6%(v/v). The flow rate of mobile phase was 1 ml/min and the UV wavelength was fixed at 210 nm. The fraction containing acanthoside-D was collected and concentrated about one hundred times by a rotary evaporator. From the chromatogram, the impurities were almost eliminated and only pure acanthoside-D was obtained. Finally on a preparative column (3.9x300 mm, 15 mum, Lichrospher 100RP-18) with the same mobile phase composition, the allowable maximum injection volume increased to 500 mul.