[Objective] To establish HPLC method that could determine simultaneously the content of three main chemical constituents like P.japonicus saponin V,P.japonicus saponin IVa and P.japonicus saponin IV in P.japonicas medicinal materials,and to study the dynamic variation of three chemical constituents of Hubei Enshi P.japonicus rhizome at different cultivating years.[Method] The content of P.japonicus saponin V,P.japonicus saponin IVa and P.japonicus saponin IV in each sample of P.japonicas rhizome was determined by HPLC.The HPLC analysis was performed on a Diamonsil C18 column(4.6 mm×250 mm,5 μm) with the detection wavelength at 203 nm.Following the injection of sample solution,an elution with acetonitrile-0.2% ammonium acetate(V/V,32:68) as mobile phase was initiated at a flow rate of 1.0 ml/min.In addition,the column temperature was 30 ℃.[Result] The calibration curve of P.japonicus saponin V,P.japonicus saponin IVa and P.japonicus saponin IV was linear in the range of 0.06-4.00 μg(r1=0.999 6),0.04-3.00 μg(r2=0.999 4),0.04-3.00 μg(r3=0.999 5),respectively.The average recovery of the above 3 chemical constituents was 100.61%(RSD=1.28%),99.06%(RSD=1.63%),101.12%(RSD=0.89%),respectively.The content of the main constituents in P.japonicus rhizome differed greatly at different cultivating years.[Conclusion] The method is simple,reliable,and can be used for determining the content of the main constituents in P.japonicus rhizome.It could provide reference to formulate standardized cultivation measures for P.japonicus by monitoring the accumulation of its main constituents. [Objective] To establish HPLC method that could determine the content of three main chemical constituents like P. japonicus saponin V, P. japonicus saponin IVa and P. japonicus saponin IV in P. japonicas medicinal materials, and to study the dynamic variation of three chemical constituents of Hubei Enshi P. japonicus rhizome at different cultivating years. [Method] The content of P. japonicus saponin V, P. japonicus saponin IVa and P. japonicus saponin IV in each sample of P. japonicas rhizome was determined by HPLC The HPLC analysis was performed on a Diamonsil C18 column (4.6 mm × 250 mm, 5 μm) with the detection wavelength at 203 nm. After the injection of sample solution, an elution with acetonitrile-0.2% ammonium acetate (V / V, 32:68) as mobile phase was initiated at a flow rate of 1.0 ml / min. In addition, the column temperature was 30 ° C. [Result] The calibration curve of P. japonicus saponin V, P. japonicus saponin IVa and P. japonicus saponin IV was linear in the range of 0.06-4.00 μ 0.04-3.00 μg (r2 = 0.999 4), 0.04-3.00 μg (r3 = 0.999 5), respectively. The average recovery of the above 3 chemical constituents was 100.61% (RSD = 1.28%) , 99.06% (RSD = 1.63%), 101.12% (RSD = 0.89%), respectively.The content of the main constituents in P.japonicus rhizome differed greatly at different cultivating years. [Conclusion] The method is simple, reliable, and can be used for determining the content of the main constituents in P. japonicus rhizome. It could provide reference to formulate standardized cultivation measures for P. japonicus by monitoring the accumulation of its main constituents.