Abstract: OBJECTIVE To explore the effects of two effective components of traditional chinese medicine(astragaloside A and oleanolic acid) on the proliferation of neural stem cells and the expression of Jagged1 mRNA in vitro. METHODS Neural stem cells were obtained from fetal mice’s brain by mechanical degestion, and randomly divided, treated with different concentration(10^-6, 5×10^-7, 10^-7, 5×10^-8, 10^-8, 5×10^-9, 10^-9 mol·L^-1) of astragaloside A and oleanolic acid. Cell proliferation was checked by WST assay after 72 h intervention. Expression of Jagged1 mRNA was checked by PCR. RESULTS There was no significant effect of astragaloside A on the proliferation of neural stem cells. The high dose of astragaloside A had cytotoxic effect. Oleanolic acid promoted the proliferation of neural stem cells which showed dose-effect relationship, compared with control group and astragaloside A, there was significant difference(P<0.05). There was some expression of Jagged1 mRNA in undifferentiational neural stem cells, and its level was up-regulated according to the rate of proliferation. The expression of Jagged1 mRNA was significant different between astragaloside A and oleanolic acid(P<0.05). CONCLUSION There are different effects on proliferation of neural stem cell and expression of Jagged1 mRNA according to the concentration and the kinds of effective components of traditional chinese medicine. The effect of oleanolic acid is better than astragaloside A.