To explore a possible new treatment for human ovarian cancer, we studied the effects of sodium valproate on the growth of the HO8910 human cell line. HO8910 cells were cultured in vitro and treated with different concentrations of sodium valproate. Cell proliferation, cell cycling, and apoptosis were measured by flow cytometry, cell morphology under a microscope, and expression levels of WWOX and P27 by Western blotting and RT-PCR. Tumor xenografts were established to determine in vivo effects of sodium valproate. Our results showed that cell proliferation was decreased with increasing concentration of sodium valproate, with features of cytoplasmic retraction and floating cells. Moreover, cell cycle analysis revealed a higher apoptosis rate and $G_0/G_1$ phase in the sodium valproate experimental group than in the control group. In addition, protein expression levels of WWOX and P27 were elevated. Importantly, sodium valproate decreased in vivo xenograft tumor burden and up-regulated WWOX and P27 expression in nude mice. In conclusion, sodium valproate might play a role in inhibition and control of ovarian cancer cell line HO8910 by inhibiting cell proliferation, interfering with the cell cycle and promoting apoptosis, so that it may be effective in the clinical treatment of ovarian cancer.