Ovarian cancer is alethal gynecologic malignancy and always has apoor prognosis. Despite new treatments modalities, the long term outcomes had not been significantly improved in the past 30 years. Although microRNA-200a (miR-200a) has been reported to be aprognostic marker in ovarian cancer, it's exact role in ovarian cancer remain unclear. In this study, we inserted the response element of miR-200a in ovarian cancer cell line via lentivirus-mediated transgene in vitro, and qRT-PCR (real time quantitative reverse transcription PCR) assay confirmed that miR-200a was up regulated compared with control. Then colony-formation assay, cell cycle analysis, CCK8 assays in vitro and xenograft experiments in vivo were performed and verified that miR-200a promoted proliferation, while blocked the formation of tumor spheroids and reduced the ratio of SP (side population) cells in ovarian cancer. Finally, we invalidated that miR-200a significantly enhanced the chemosensitivity of paclitaxel but not cisplatin in both adherent culture and sphere culture. Taken together, we demonstrated that upregulation miR-200a promoted proliferation and inhibited CSCs phenotype in OVCAR-3 ovarian cancer cell line, combined with cell cycle-targeting drug paclitaxel could effectively eliminate the "side effects" of proliferation, and showed evidences that this strategy may be promising for ovarian cancer treatment.