Objective To investigate the effect of blood glucose on the outcome of patients with acute ischemic stroke.Methods According to their blood glucose levels, 240 patients with acute ischemic stroke were divided into normal blood glucose (NBG) and high blood glucose (HBG) groups. Following different periods of treatment (15 days, 30 days, and 3 months), nerve function defect and clinical outcome in the two groups of patients were evaluated using the National Institutes of Health Stroke Scale (NIHSS) and Modified Rankin Scale (MRS), respectively.Results The NIHSS score had no significant difference between groups after 15 days of treatment (P>0.05) and was significantly higher in the HBG group than in the NBG group after 30 days and 3 months of treatment (P<0.05). The MRS score showed no significant difference between groups after 15 and 30 days of treatment (P>0.05), and was significantly lower in the HBG group than in the NBG group after 3 months of treatment (P<0.05). Conclusions High blood glucose is one of the factors aggravating nerve function defect and affecting the clinical outcome in patients with acute ischemic stroke. Proper regulation of blood glucose levels is of great importance for the outcome of acute ischemic stroke.