OBJECTIVE： To study the mechanism of improvement effects of exenatide on mitochondrial function of H9c2 cells under hypoxia/reoxygenation （H/R） condition. METHODS： H9c2 cells were cultured in vitro and were divided into blank control group， drug control group （exenatide 200 nmol/L）， model group （H/R）， pretreatment group （exenatide 200 nmol/L+H/R）， glucagon-like peptide-1 receptor （GLP-1R） inhibitor [Exendin-（9-39） 100 nmol/L+exenatide 200 nmol/L+H/R]， cAMP inhibitor （Rp-cAMPS 1 μmol/L+exenatide 200 nmol/L+H/R） group and PKA inhibitor （H-89 5 μmol/L+exenatide 200 nmol/L+H/R） group. Except for first 2 groups， H/R model was established in other groups， and they were given exenatide 30 min before modeling and relevant inhibitor 10 min before giving exenatide. Morphology of mitochondria was observed by TEM， and mitochondrial calcium （Ca2+m） and the mitochondrial membrane potential （ΔΨm） were determined by flow cytometry. Cellular ATP content was measured by microplate reader. RESULTS： Compared with blank control group， mitochondrial cristae swelling was enhanced in model group， while density decreased， showing vacuolization； Ca2+m level increased while ΔΨm and ATP decreased （P＜0.05）. Compared with model group， mitochondrial cristae swelling relieved in pretreatment group， while density increased， showing vacuolization relieved； Ca2+m level decreased， while ΔΨm and ATP increased （P＜0.05）. Compared with pretreatment group， the levels of Ca2+m increased in 3 kinds of inhibitors group， while ΔΨm and ATP decreased （P＜0.05）. CONCLUSIONS： Exenatide attenuates H9c2 cell mitochondria Ca2+m accumulation， increases ΔΨm and ATP production. Which indicate its mechanism may be associated with activating GLP-1R/cAMP/PKA pathway.