Objective :Establish a method for determining the content of water soluble saponins of Rhizoma Dioscoreae Nipponicae which grow in Daxinganling area of Heilongjiang Province. Method: RP HPLC was used on an Diamonsil C18 column(4.6 mm×250 mm

5 μm) with acetomitrile-water as mobile phase by gradient elution for the separation and determination of saponins of Rhizoma Dioscoreae Nipponicae

the detection wavelength was at 203 nm

column temperature 30 ℃. Result :The linear ranges were 50-500 mg·L-1 for protodioscin concentration

35-350 mg·L-1 for methyl protodioscin concentration

15-150 mg·L-1 for pseudoprotodioscin concentration

the calibration curve of each solvent had good linear relationship within the range with a correlation coefficient of 0.999 9(n=6). On the basis of methodology of the test results show RSD <3%. Conclusion :All the results show that the method has good reproducibility

recovery rate and stability. This has provided a basis for Rhizoma Dioscoreae Nipponicae quality control.