Sevoflurane is an inhalational anesthetic widely used in clinical settings. Accumulating evidence has shown that sevoflurane exposure may impair cognitive function, potentially contributing to Alzheimer's disease (AD)-related changes. However, the underlying mechanism remains poorly understood. In the present study, 4-month-old 5xFAD mice were used to investigate the effect of sevoflurane exposure on cognitive decline by Y-maze test and novel object recognition test. We found that sevoflurane exposure promoted the appearance of cognitive impairment of 5xFAD mice, accompanied with the deterioration of Aβ accumulation, synaptic defects, and neuroinflammation. Additionally, sevoflurane was also found to aggravate mitochondrial fission of 5xFAD mice, as indicated by the further upregulated expression of p-Drp1. Moreover, sevoflurane significantly increased mitochondrial damage and dysfunction of AD models both in vitro and in vivo experiments. Seahorse XF analysis further indicated that sevoflurane exposure facilitated a metabolic shift from oxidative phosphorylation to glycolysis. Further rescue experiments revealed that a key mechanism underlying sevoflurane-induced cognitive impairment was the excessive mitochondrial fission, as supported by the result that the mitochondrial fission inhibitor Mdivi-1 counteracted the sevoflurane-mediated deteriorative effects in 5xFAD mice. These findings provided evidence for a new mechanism of sevoflurane exposure accelerating AD-related cognitive decline.