Abstract: Objective To investigate whether the methylene tetrahydrofolate reductase (MTHFR) 677C/T polymorphisms were related to the prevalence of 46，XX premature ovarian failure (POF) in Chinese Han women. Methods Infertile Chinese Han women were divided into 2 groups: POF group (n=147) and control group (n=166).The expression of MTHFR gene in peripheral blood was determined by RT-PCR. The 677C/T genotype of MTHFR gene was identified by restriction fragment length polymorphism (RFLP). Genotype frequencies and allele frequencies were counted. PCR product were randomly examined for gene sequencing to verify whether the amplified fragment. Relationship between MTHFR gene polymorphism and clinical characteristics of idiopathic POF was analyzed. Results The results of gene sequencing showed that the PCR amplification fragment was the target gene fragment, and the sequencing showed that the genotype was 100% consistent with the enzymatic display genotype. The MTHFR 677C/T genotype distribution in both the POF group and the control group was consistent with the Hardy-Weinbreg balance law (P>0.05). The frequencies of CC, CT and TT genotypes of MTHFR 677C/T were 48.3%, 40.8% and 10.9% in the POF group, and 37.3%, 47.6% and 15.1% in the control group, respectively. There was no statistically significant difference in the frequency of genotypes between the two groups (χ2=4.04, P>0.05). The T, C allele frequencies were 31.3% and 68.7% in POF, 38.9% and 61.1% in control group, there were no significant differences in the frequencies of T, C alleles between the two groups (χ2=3.90, P=0.05).Subgroup analyzes in POF group, no significant difference were detected between CC and CT+TT genotypes in menopause age, FSH, E2, endometrial thickness and antral follicle number. Conclusion The distribution of the MTHFR 677C/T polymorphisms in Chinese Han POF population was not significantly different from controls, implying that MTHFR gene polymorphisms may not be the risk factor of idiopathic POF occurred in Chinese.