Abstract: Objective: To recognize further the effects of blood glucose level（BGL） on prognosis of patients with acute cerebral infarction（ACI） complicated by diabetes mellitus（DM）. Methods: The effects of DM and its BGL on prognosis of patients with ACI complicated by DM were analyzed by meta-analysis in homogeneity test and combined test in 15 studies. All patients were divided into A B C three groups according to theirs fasting BGL, they are blood glucose＜11.1mmol/L,≥11.1-＜ 16.7mmol/L and≥16.7mmol/L respectively. Results: （1）Homogeneity test shows that the cited studies are homogeneous with P＞0.05;and （2）combined test shows that the prognosis in normal blood glucose group was significantly better than that in DM group （OR=4.05,95%CI=4.60-5.19）, while risk of death in DM group was significantly higher than that in normal blood glucose group （OR=3.60,95% CI=2.36-5.49）（P＜0.001）.There was not significant difference in prognosis between A group and B group（P＞0.05）, but there was significant difference in prognosis between A group and C group or between B group and C group（P＜0.001）. The mortalities of A B C three groups was 0, 6.16% and 40.17% respectively. There were significant differences in mortalities between three groups（P＜0.005）.Conclusion: The patients with ACI complicated by DM has poor prognosis, and the higher the BGL, the worse the prognosis.