Abstract: Objective:To investigate the effect of Saponin I of Schizocapsa plantaginea Hance (SSPHI) on the growth of pancreatic cancer transplanted in nude mice and its mechanism.Methods:The human pancreatic cancer cell PANNC-1 model was established in nude mice and the cancer forming nude mice were randomly divided into model group, gemcitabine(GEM)group, low-dose SSPHI(SSPHI-L)group, middle-dose SSPHI(SSPHI-M)group and high-dose SSPHI (SSPHI-H) group.After 15 days of continuous administration, volume tissues were dissected to measure tumor volume and tumor weight, and the tumor inhibition rate was calculated.The histopathological morphological changes of transplanted human pancreatic cancer tissues were observed by hematoxylin and eosin (HE) staining.The apoptosis of pancreatic cancer tissues was observed by TUNEL assay.The expression levels of Bcl-2, Bax, Caspase-9 and Caspase-3 in the transplanted pancreatic cancer tissues of the nude mice were detected by immunohistochemistry.Results:Compared with the model group, the tumor volume and tumor weight in the low-, middle-and high-dose SSPHI groups and GEM group were reduced, the apoptosis rate increased (P< 0.01), Caspase-9, Caspase-3 and Bax protein expression levels in the transplanted cancer tissues increased, and Bcl-2 protein expression level decreased (P< 0.01).Conclusion:SSPH I can inhibit the growth of pancreatic cancer transplanted in nude mice and its effect may be related to down-regulating the expression of Bcl-2, up-regulating the expressions of Bax, Caspase-9 and Caspase-3, and inducing the apoptosis of transplanted tumor cells.