Abstract：Objective To investigate the MTHFR C677T gene locus in patients with H-type hypertension complicated with ischemic stroke, and to explore its correlation with the levels of Hcy and folic acid. Methods 34 patients with H-type hypertension complicated with ischemic stroke in group A, 36 patients with ischemic stroke in group B and 32 cases without the history of stroke and hypertension and other chronic diseases in group C were diagnosed and treated at the Central Hospital Affiliated to Shenyang Medical College from December 2017 to January 2019 were selected. The MTHFR C677T gene locus and the levels of Hcy and folic acid were measured in three groups. Results （1）The differences of genotypes and allele frequencies between groups A , B and group C were statistically significant（both P＜0.05）; there was no significant difference between groups A and B（P＞0.05）.（2）The Hcy of TT type was the highest among the 3 groups, and the Hcy of group A was the highest among the 3 groups. （3）There was a negative correlation between Hcy and folic acid in groups A and B, and the difference was statistically significant （P＜0.05）; there was no correlation between Hcy and folic acid in group C. Conclusion The MTHFR C677T gene in patients with H-type hypertension complicated with ischemic stroke is polymorphic, and mutations in the gene can increase Hcy. Folic acid is negatively correlated with Hcy. Folic acid can reduce the incidence of ischemic stroke in patients with H-type hypertension.