Abstract: Objective: To explore the inhibition effects of NK-92 cells on the Her-2 gene expression in SKOV-3 cells in vitro and in vivo.Methods: The SKOV-3/siRNA cell line with persistent silencing the Her2 gene expression were established by the siRNA targeting Her2 gene transfecting into SKOV-3 cell line.The inhibition effects on Her2 gene mRNA expression were detected by RT-PCR and immunohistochemistry.The killing activity of NK-92 cells to SKOV-3 and SKOV-3/siRNA was detected by LDH.The tumor growth in the nude mice inoculated with SKOV-3 and SKOV-3/siRNA subcutaneously was observed.The effects of NK-92 cells on ovarian cancer in all cases were compared.Results: The SKOV-3/siRNA cell line with persistent silencing the Her2 gene expression was established,the Her2 gene expression was strong inhibited.The killing rates of NK-92 cells to SKOV-3 and SKOV-3/siRNA were(21.1±6.8)% and(45.5±8.9)% at 1：20 of the target ratio,respectively(P<0.01).The tumor volume in mice inoculated with SKOV-3/siRN cells was significantly less than that in mice inoculated with ASKOV-3(P<0.05 to P<0.01),The tumor quality in mice treated with SKOV-3/siRN combined with NK-92 cells were significantly less than that in other mice(P<0.05 to P<0.01).Conclusions: NK-92 cells combined with siRNA targeting Her2 gene can inhibit the proliferation of the ovarian cancer cell line SKOV-3 in vitro and in vivo,which may become a new approach of ovarian cancer therapy.