Per- and polyfluoroalkyl substances (PFAS), the versatile anthropogenic chemicals, are popular with the markets and manufactured in large quantities yearly. Accumulation of PFAS has various adverse health effects on human. Albeit certain members of PFAS were found to have genotoxicity in previous studies, the mechanisms underlying their effects on DNA damage repair remain unclear. Here, we investigated the effects of Perfluorodecanoic acid (PFDA) on DNA damage and DNA damage repair in ovarian epithelial cells through a series of in vivo and in vitro experiments. At environmentally relevant concentration, we firstly found that PFDA can cause DNA damage in primary mouse ovarian epithelial cells and IOSE-80 cells. Moreover, nuclear cGAS increased in PFDA-treated cells, which leaded to the efficiency of DNA homologous recombination (HR) decreased and DNA double-strand breaks perpetuated. In vivo experiments also verified that PFDA can induce more DNA double-strand breaks lesions and nuclear cGAS in ovarian tissue. Taken together, our results unveiled that low dose PFDA can cause deleterious effects on DNA and DNA damage repair (DDR) in ovarian epithelial cells and induce genomic instability.