Multiple cell signaling pathways and biological processes are involved in cerebralischemia/reperfusion (I/R)injury，among which，autophagy is a most confusmg one．Studiessuggest that autophagy is activated during ischemia and reperfusion (I/R)，however theresno data to dynamically mimic autophagy level during the whole process of I/R，and its stillnot known whether autophagy functions as a guardian or plays a detrimental role in I/RinJury． Here we employed simulated I/R of N2a cells (mouse neuroblastoma cells)as an in vitromodel of I/R injury to the neurons．LC-311 level was checked by immunoblot analysis atdifferent time points of ischemia process，and different intervals of reperfusion．Resultsshowed that autophagy was gradually activated as ischemia went on，and greatly elevatedduring the process of reperfusion after 90minutes ischemia insult．I/R manipulation wasalso applied to N2a cells transfected with EGFP-LC3，punctate EGFP-LC3 was monitored,percentage of cells displaying obvious EGFP-LC3 puncta coincided with the forenamedimmunoblot results．Also，we found that autophagy was induced in hippocampus andcortex of rats underwent MCAO for 90 minutes and reperfusion for a week． Beclin-1 in cytosol，p-mTOR，p-P70 S6K were also checked in ischemia/reperfusiongroups by immunoblot analysis，results indicated that Beclin-1 in cytosol shared the samechange pattern with LC-311，while p-P70 S6K and p-mTOR showed delayed decrease afterreperfusion．Administration of 3MA，inhibitor of class Ⅲ PI3K，definitely abolishedautophagy during reperfusion，while employment of rapamycin，inhibitor of mTORC1,surprisingly weakened autophagy activation during reperfusion． Analyses of mitochondria function by relative cell viability were performed in I/R modelgroups and 3MA-treated groups，results came that autophagy inhibition by 3MA definitelyhold back the decline of mitochondria function during the process of reperfusion.