Objective To study the correlation between homocysteine levels and MTHFR C677T gene polymorphism of cerebral infarction.Methods Four hundred and fifty patients with cerebral infarction in our hospital were selected as the study group from February 2012 to August 2015,including 181 diabetes patients and 269 non-diabetic patients.Also 285 cases of physical examination healthy people in the outpatient department were selected as the control group.The MTHFR C677T polymorphism and the correlation between genotype and Hcy levels were analyzed by pyrosequencing.Results The difference of distributions of MTHFR genotype between the study group and the control group was statistically significant (P ＜ 0.05).The frequency of the T gene in the study group was significantly higher than the control group,the difference was statistically significant (x2 =13.67,P =0.00).The Hcy concentrations of the study group was significantly higher than the control group,and the difference was statistically significant (t =12.71,P =0.00).The Hcy levels of different MTHFR genotype in the cerebral infarction patients were statistically significant (F =17.68,P =0.00).Hcy levels in non-diabetic patients with cerebral infarction was significantly higher than in diabetic patients with cerebral infarction,and the difference was statistically significant (t =2.97,P =0.00).Hcy concentrations of TT genotype of non-diabetic group was significantly higher than the TT genotype of the diabetic group,CC type Hcy concentration significantly lower than the diabetic group,and the differences were statistically significant (t =5.67,2.18;P =0.00,0.03).In cerebral infarction patients both with non-diabetic and diabetic,the Hcy levels of MTHFR gene TT genotype were significantly higher than those of CC and CT genotype,and the differences were statistically significant (P ＜ 0.05),and the differences of Hcy levels between the genotype of CT and CC was not statistically significant (P ＞ 0.05).Conclusion The T allele frequency of MTHFR C677T in the cerebral infarction patients is much higher than healthy people.MTHFR TT genotype is related to serum Hcy levels.Maybe it is a risk factor for cerebral infarction.