Ovarian cancer (OC) is often diagnosed in its advanced stages with many patients suffering from recurrence. Relapse is frequent after standard treatment leading to platinum resistance and poor prognosis in patients. Several studies have reported that immune status and inflammatory factors, such as Interleukin-17D (IL -17D), are major players in the prognosis of malignant tumors. IL -17 family is an important pro -inflammatory cytokine family, which mediates immunosuppression and promotes tumor progression. Our previous exploration revealed the promoting role of IL -17D expression in the occurrence and development of ovarian carcinoma, but the specific mechanism remains unclear. In this study, we investigated the effects of rhIL-17D on the proliferation, migration and invasion of human ovarian carcinoma cell SKOV3 in vitro. In addition, we also detected the effect of rhIL-17D on programmed death ligand1 (PD -L1) expression of SKOV3 cells and possible mechanism.We found that rhIL17D accelerated SKOV3 cell proliferation rate, enhanced the migration and penetration ability, and promoted the expression of PD -L1. After knockdown P65 expression,the activated form of NF -KB, in SKOV3 cells, the proliferation activity, migration, and invasion of ovarian cancer cells were significantly reduced. And the expression of PDL1 decreased. In summary, we believe that IL -17D can accelerate cell proliferation and enhance cell migration and invasion abilities of ovarian cancer and induce PD -L1 expression by regulating the activation of NF -KB pathway. Down -regulation of IL -17D in tumor microenvironment may be a new approach to inhibit ovarian cancer.