Objective To observe the effects of Radix Cynanchum auriculatum extract in mice with vascular dementia.Methods An animal model was established through repeated cerebral ischemia-reperfusion in mice with tail bleeding hypotension.Morris water-mase was used to determine the learning and memory ability；gasping time of mice by decapitation were evaluated.Changes in superoxide dimutase(SOD)，malonaldehyde(MDA)were observed by means of spectro photometry.Results To contrast high dose drug group with model group，the escape latencies were significantly shorter(P＜0.01)，contrarily the time in correct zone were prolonged(P＜0.01).And the gasping time of mice by decapitation were also protracted[(19.3±1.6)s vs(15.7±0.7)s](P＜0.01).The high dose group had less content of MDA[(5.12±1.09)nmol·mgprot-1 vs(6.77±0.96)nmol·mgprot-1](P＜0.01)，but more activity of SOD in hippocampus and cerebral cortex[(121.0±14.2)U·mgprot-1 vs(101.5±9.4)U·mgprot-1](P＜0.05).Conclusion Radix Cynanchum auriculatum extract has protective effect on cerebral ischemia-reperfusion injury.The mechanism may be related with anti-oxidation and free radical.