Objective：To investigate the effects of different concentrations of sevoflurane anesthesia on cognitive function in aged rats. Methods：Eighty SD rats were randomy divided into 5 groups：0% sevoflurane group（C，n=16），1% sevoflurane group（S1，n=16），2% sevoflurane group（S2，n=16），3% sevoflurane group（S3，n=16） and 4% sevoflurane group（S4，n=16）. All rats received anesthesia for 6 h. Cognitive function was tested with Morris watermaze. Amyloid precursor protein（APP），β-amyloid peptide（Aβ） and human beta-site APP-cleaving enzyme-1（BACE-1） expressions in the hippocampus were determined with ELISA. Results：（1）Morris watermaze test and spatial probe test demonstrated that both latency and the number of seeking for hidden-platform were significantly decreased in S3 and S4 groups than in control group（P<0.05），but no significant difference between S1 and S2 groups was found（P >0.05）. （2）Ex－pressions of APP and Aβ in the hippocampus were increased with increase of concentrations（P<0.05）. （3）Expressions of BACE-1 in hippocampal were significant increased in S3 and S4 groups than in control group（P<0.05）. Conclusions：Sevoflurane inhibits cognitive function of aged rats in dose-dependent manner. These results suggest high concentration sevoflurane could induce APP and Aβ and result in the up-regulation of BACE-1 expressions.