Objective To investigate the relationship between the plasma homocysteine (Hcy) and cerebral infarction.Methods 84 patients with cerebral infarction in our department were selected as study group and 56 cases from medical examination center were selected as control group. The fasting plasma homocysteine (Hcy) was determined in both groups . Result The level of Hcy in cerebral infarction group was significantly higher than the control group, there was a significant difference ( <0.01) .Conclusion High homocysteine levels is an important independent risk factor of cerebral infarction.