Objective To investigate the mechanism of the miR-518a-5p / histone deacetylase 6 (HDAC6)axis in DNA oxidative damage in ovarian cancer (OC) SKOV3 cells. Methods Expression levels of miR-518a-5p and HDAC6 mRNA in OC tissues and in various cancer cells (A2780, SKOV3, CAOV3) were detected by qRTPCR. SKOV3 cells were separated into Control, miR-NC, miR-518a-5p mimics, miR-518a-5p mimics+pcDNA-NC,and miR-518a-5p mimics+pc-HDAC6 groups. Cell proliferation and apoptosis were analyzed by colony-forming assay and Hoechst 33258 staining. Expression of phosphorylated histone H2AX ( γ-H2AX ) was detected by immunofluorescence assay and reactive oxygen species ( ROS) were detected by flow cytometry. HDAC6, Bcl-2-associated X protein (Bax), and B-cell lymphoma-2 (Bcl-2) protein expression were analyzed by Western blot. The regulatory relationship between miR-518a-5p and HDAC6 was analyzed by dual luciferase assay. The effect and mechanism of miR-518a-5p on oxidative DNA damage in OC cells were studied in a xenotransplantation tumor model. Results miR-518a-5p expression was decreased and HDAC6 expression was increased in OC tissues and A2780,SKOV3, and CAOV3 cells ( P< 0. 001). Expression levels of miR-518a-5p were lowest and expression levels of HDAC6 were highest in SKOV3 cells, and SKOV3 cells were therefore selected for subsequent experiments. miR-518a-5p expression, apoptosis rate, number of γ-H2AX-positive cells, relative ROS fluorescence intensity, and expression of Bax were all higher in the miR-518a-5p mimics group compared with the miR-NC group, while HDAC6 mRNA and protein expression, Bcl-2 expression, and colony-formation number were all lower (P<0. 001). HDAC6 mRNA and protein expression, colony-formation number, and expression of Bcl-2 were higher in the miR-518a-5p mimics+pc-HDAC6 group compared with the miR-518a-5p mimics+pcDNA-NC group, and the apoptosis rate, number of γ-H2AX-positive cells, relative ROS fluorescence intensity, and expression of Bax were all lower (P< 0. 001).HDAC6 had a targeted regulatory relationship with miR-518a-5p. Overexpression of miR-518a-5p decreased tumor volume, weight, and HDAC6 protein expression in tumor tissues, and increased γ-H2AX expression in vivo ( P<0. 001). Upregulation of HDAC6 expression by overexpression of miR-518a-5p increased graft tumor volume, weight,and HDAC6 protein expression and decreased γ-H2AX-positive expression (P<0. 05). Conclusions miR-518a-5p expression is reduced and HDAC6 expression is increased in OC tissues and cells. Overexpression of miR-518a-5p can induce oxidative DNA damage in SKOV3 cells by inhibiting HDAC6 expression, thereby inhibiting cell proliferation and promoting cell apoptosis.