In the study, we first constructed the recombinant lentiviral vector for lasting the expression of IL-21, and then the hUCMSCs transducted by IL-21 gene packaged lentivirus had been injected into mouse ovarian cancer model to assess the effect of hUCMSCs-LV-IL-21 on ovarian cancer in vivo. Here, IL21 is linked to ovarian carcinoma.