In order to evaluate the efficacy of hUCMSCs-LV-IL-21 therapy for ovarian cancer in the mice, we first established the ovarian cancer bearing mouse model by injection of 5 × 106 SKOV3 cells in a mouse’s flank, and then we tested whether injection of 1 × 106 hUCMSCs-LV-IL-21 could inhibit the SKOV3 ovarian cancer growth in the mouse model. The gene discussed is IL21; the disease is ovarian cancer.