Objective Establishment of a middle cerebral artery occlusion（middle cerebral artery occlusion，MCAO）model in both young and aged rats with equivalent levels of neurological impairment，in order to avoid inaccurate experimental results of drug effi⁃ cacy and toxicology caused by bias in animal models of cerebral ischemia.Methods Male Sprage-Dawley rats were used in this study.After exploring the suitable suture for aged rats，the rats were randomly divided into 4 groups: Young sham group（n = 20），Aged sham group（n = 20），Young MCAO group（n = 20），and Aged MCAO group（n = 20）.The MCAO model with the same degree of neurologi⁃ cal impairment was established in the Young MCAO group and the Aged MCAO group.Brain injury was evaluated by modified neuro⁃ logical function score（mNSS），Angle test and assessment of apoptosis in the infarct area.Results In young rats，the diameter of the sili⁃ cone tip was 0.32 mm and the insertion depth was（18 ± 2）mm.In aged rats，the diameter of the silicone tip was 0.43 mm and the inser⁃ tion depth was（22 ± 2）mm.By adjusting the suture position，when local cerebral blood flow（rCBF）was 15% of the baseline blood flow in young rats and 25% of the baseline blood flow in aged rats，there was no significant difference in the level of neurological injury within 3 days after operation（P > 0.05），and the degree of apoptosis in the infarcted area was equal（P > 0.05）.Conclusion By regu⁃ lating rat rCBF，it is possible to control the degree of brain damage and establish a rat MCAO model with the same level of neurological function damage in young and old rats，which can be used for related research on cerebral ischemia.This helps to avoid inaccurate ex⁃ perimental results of drug efficacy and toxicology mechanisms caused by bias in animal models of cerebral ischemia.