Objective：To investigate the distribution of methylenetetra-hydrofolate reductase（MTHFR） genotypes in community popu－lation，and explore the relationship between MTHFR c677t polymorphisms and intracranial atherosclerotic stenosis. Methods：Six hundred and ninety-eight adult Han people were selected from the people undergoing physical examination in the First Affiliated Hospital of Chongqing Medical University from January 2016 to May 2017 by convenience sampling. Their past medical history，and physiological and biochemical indicators were recorded. The MTHFR c677 genotypes of target group were detected by polymerase chain reaction-restriction fragment length polymorphism（PCR-RFLP），and the intracranial atherosclerotic stenosis（ICAS） by transcranial Doppler（TCD）. The results were analyzed by Chi-square test for statistical difference and multiple factor logistic regressions for the correlated influencing factors of ICAS. Results：There was significant distribution difference between the ICAS and NICAS group of allele frequencies（C/T + T/T and C/C， χ2=13.347，P=0.000）. The differences between the genotype groups are also significant（T/T and C/C， χ2=12.064，P=0.001；and C/T and C/C， χ2=10.414，P=0.000）. The frequencies of T allele in community population with ICAS were obviously higher than those of the control. The multiple factor logistic regression analysis showed that T/T（OR=2.34，95%CI=1.363 to 4.016，P=0.002） genotype and C/T（OR=2.34，95%CI=1.363 to 4.016，P=0.002） genotype were probably the independent risk factor for intracranial atherosclerotic stenosis. Conclusion：There is a genetic polymorphism of MTHFR c677t in community population in China，which is correlated with the increased risk of ICAS.