〔Abstract〕 Objective To investigate the therapeutic effects of human placental mesenchymal stem cells(hPMSCs) on asthmatic rats and the effects of Notch signaling pathway related factors. Methods Thirty SD rats were randomly divided into three groups: control group, asthma model group(OVA group) and hPMSCs transplantation group(hPMSCs group), 10 rats/group. The morphological changes of lung tissue were observed by HE staining. The inflammatory factors in rat serum were detected by ELISA. The Notch1, Notch2, Notch3 and Jagged1 mRNA and protein in rat lung tissue were detected by RT-qPCR and Western blot. Results HE staining results showed that compared with OVA group, the lumen of hPMSCs group was slightly constricted and inflammatory cell infiltration was alleviated. ELISA results showed that serum immunoglobulin E(IgE) and interleukin 4(IL-4) levels in OVA group were higher than those in control group(P<0.05), while interferon-γ(IFN-γ) level was lower(P<0.05).Compared with OVA group, the levels of IgE and IL-4 in serum of hPMSCs group decreased(P<0.05), while the levels of IFN-γ in serum increased(P<0.05). The results of RT-qPCR and Western blot showed that the expressions of Notch1, Notch2 and Jagged1 mRNA and protein in lung tissue of OVA group were higher than those of control group, while the expression of Notch3 mRNA and protein was lower. Compared with OVA group, the expression of Notch1, Notch2, Jagged1 and Notch3 mRNA and protein in hPMSCs group decreased, while the expression of Notch3 mRNA and protein increased. Conclusion hPMSCs can inhibit the inflammatory response of asthmatic rats by regulating Notch signaling pathway and play a role in the treatment of asthma.