Objective:To establish a HPLC for determination of Gracillin in Rhizoma Paridis and Yunnan white on the bases of determining anti tumor cytotoxic bioactivities of more than 20 varieties of chinese medical materials and traditional Chinese patent medicines.Methods: The determination was carried out by HPLC on KR 100-5C18 column, with acetoitrile water (43∶5) as a mobile phase. The detection wavelength was 210nm. and the flow rate was 0.8ml/min.Results: The recoveries are 99.8% (RSD in 2.6%, n=6) and 98.8% (RSD is 1.5%, n=6), respechrely. The within day and between day accuracies are 1.4% of RSD(n=6) and 1.8% of RSD (n=4), respectively.Conclusion: The results showed that water, methanol and alcohol extracts of Rhizoma Paridis and Yunnan white had strong inhibition on 6 kinds of neoplasm cells of human body and their component Grarillin also had the inhibition on tumor cells.