Objective To investigate the molecular mechanism of miR-34a in facilitating cochlear hair cell (HEI-OC1) apoptosis by modulating SESN2 expression.Methods Dualluciferase reporter gene assay detected the targeted correlation between SESN2 and miR-34a. The negative control group (NC), miR-34a-overexpression group (miR-34a mimic), SESN2-overexpression group (SESN2) and the cotransfected group (SESN2+miR-34a mimic) cell lines were constructed respectively. qRT-PCR was used to detect the correlation between miR-34a and SESN2 in HEI-OC1 cells. CCK-8 was proposed to detect the changes in cell proliferation ability. The cell apoptotic rates were measured by flow cytometry.ELISA was used to detect the expression of SOD, CAT, GSH-Px and MDA while the expression of AMPK-related signaling factors were detected by WB. Results Dual-luciferase reporter assay showed that the luciferase activity was significantly inhibited after cotransfected with miR-34a mimic and pGL3-PIK3CA-ESN2-WT plasmids. The expression of miR-34a and SESN2 in HIE-OC1 cells were mutually inhibited. Overexpression of SESN2 significantly promote HEI-OC1 cell proliferation, suppress apoptotic rates and increased the intracellular level of antioxidative stress when compared with the NC group. Conversely, miR-34a-overexpression will weaken the protective effect of SESN2 on HEI-OC2 cells. Overexpression of SESN2 also promotes the relative expression of the anti-apoptotic proteins Bcl-2 and SIRT1, p-AMPK while the expression of apoptotic proteins Bax, caspase-3 were suppressed. The intracellular antioxidant stress factors SOD, CAT and GSH-Px increased with the increase of SESN2 while the expression of MDA was decreased. Conversely, cotransfection with miR34a mimic reverse the abovementioned molecular expression changes. Conclusion miR-34a may activate AMPK/SIRT1 signaling pathway and accelerate intracellular oxidative damage by targeted inhibition of SENS2 which cause the apoptosis of HEI-OC1 cells.