Objective Recent studies have shown that general anesthesia induces memory impairment. Sevoflurane, an inhalation anesthetic, is widely used in clinical practice, increasing pieces of evidence suggest that sevoflurane impairs memory processes due to changing gene expression in hippocampus. In our previous study, we found sevoflurane changed the expression of 417 genes by using mircoarray. In the present study, we, in one hand, demonstrated the result of circadian gene expression from microarray detection during sevoflurane anesthesia; on the other hand, we investigated weather there were time-course or dose-dependent relation between sevoflurane and circadian gene expression. Methods In the expriment, six-week-old male Sprague-Dawley rats were anesthetized for 4 h with 2.5% sevoflurane (n=6) and were sacrificed 48 h later. RNA was extracted from the hippocampus, the gene expression was performed by real-time quantatitive PCR. Results The results indicated that among six circadian genes including Per2, Dbp, Arc, Egr1 and Krox20, only Egr and Per had dose-dependent relation, the other four genes had no obvious the relation. However, six genes had significant time-course relation.Their expression level tended to normal level 10 day after anesthesia. Conclusion Our conclusion is drawn out that sevofluran has an obvious effect on the expression of circadian genes in hippocampus, these changes could last long-term (at least 10 days) , which may be related to the memory impairment or the other neural disorders.