Abstract: Objective: To observe the inhibitory effects of genistein (GEN) on angiogenesis and growth of transplanted human ovarian cancer cells in nude mice. Methods: The transplantation models of human ovarian cancer in 20 nude mice were set up and were randomly divided into the control, lowdose GEN, medium-dose and high-dose groups. Intragastric administration was carried out in all the groups, with 5 mg/kg·d in the low-dose group, 25 mg/ kg·d in the medium-dose group and 50 mg/ kg· d in the high-dose group. This treatment last 4 weeks. Intragastric administration of deionized water of the same volume was conducted in the controls. The inhibition rate in the 3 groups was observed. Polyclonal antibody of Ⅷ factor antigen was employed to detect the intratumoral macrovascular density (MVD). Cell proliferation index(PI) was used to compare the state of cell proliferation. Histological features were observed with electron microscopy. Results: The inhibition rate in the low-dose, mediumdose and high-dose GEN groups was 1.9%, 18.50% and 38.07%, respectively. There was a significant difference in the weight of tumors between the control group and the medium-dose and high-dose GEN groups(P<0.05). There was a significant difference in MVD and PI values between the control group and the medium-dose and the high-dose GEN groups(P<0.05). Electron microscopy observation showed that with increased GEN dose, the number of apoptotic cells and denatured necrosis increased, which was seldom seen in the control group. Conclusion: GEN has an obvious inhibitory action on the human ovarian cancer cell line HO-8910PMtransplanted in nude mice, with a dose-dependent effect. GEN inhibits tumor cell proliferation and new vessel growth in the tumor area, thus blockading tumor blood supply.