Objective:To analyze the mechanism of neuroprotection of insulin and which blood glucose range was benefit for insulin exerting neuroprotective action.Data Sources:The study is based on the data from PubMed.Study Selection:Articles were selected with the search terms insulin,blood glucose,neuroprotection,brain,glycogen,cerebral ischemia,neuronal necrosis,glutamate,γ-aminobutyric acid.Results:Insulin has neuroprotection.The mechanisms include the regulation of neurotransmitter,promoting glycogen synthesis,and inhibition of neuronal necrosis and apoptosis.Insulin could play its role in neuroprotection by avoiding hypoglycemia and hyperglycemia.Conclusions:Intermittent and long-term infusion insulin may be a benefit for patients with ischemic brain damage at blood glucose 6-9 mmol/L.