Surgery under general anesthesia leads to neural injury, especially in older patients. Sevoflurane anesthesia without surgery for 2 h does not induce neural injury, however, whether prolonger sevoflurane anesthesia without surgery has the same consequence is still unknown. In the present study, aged marmosets were exposed to a clinical concentration of sevoflurane (1.5-2%) for 6 h to access the effects of prolonged sevoflurane anesthesia on the levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), Caspase3 activity and myelin formation in the brain. Sevoflurane anesthesia did not alter the expression of IL-6 (120.1 ± 2.21 vs. 120.8 ± 2.25, p = 0.74), TNF-α (189.3 ± 31.35 vs. 218.7 ± 21.47, p = 0.25) and Caspase3 (57.35 ± 1.54 vs. 58.67 ± 1.19, p = 0.53) in the prefrontal cortex (PFC) of aged marmosets. The amount of MBP expression (60.99 ± 6.21 vs. 58.91 ± 2.71, p = 0.77) did not change following sevoflurane exposure. Sevoflurane anesthesia did not increase the levels of IL-6 and TNF-α, activated the the expression of Caspase3, and induced myelination deficits in the PFC of aged marmosets.